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ROOF  FRAMING  MADE  EASY 


BY 


OWEN   B.    MAGINNIS, 

Instructor  of  Drawing  in  New  York  Trade  School. 


Author  of  "How  to  Frame  a  House,"  "Practical  Centring,"  "  How  to  Join  Moldings,"  etc. 


A  practical  and  easily  comprehended  system  of  laying  out  and  framing 
roofs,  adapted  to  modern  construction.     The  methods  are 
made  clear  and  intelligible  by  76  engravings 
with  extensive  explanatory  text. 


PUBLISHED    BY 

OWEN  B.  MAGrNNIS,  NEW  YORK. 
1896. 


Copyrighted,    1896, 

BY 
OWEN    B.    MAGINNIS. 


CONTENTS 


CHAPTER  I. 

CHAPTER  II. 
CHAPTER  III. 
CHAPTER  IY. 
CHAPTER  V. 
CHAPTER  VI. 
CHAPTER  VII. 
CHAPTER  VIII. 
CHAPTER  IX. 

CHAPTER  X. 
CHAPTER  XI. 
CHAPTER  XII. 
CHAPTER  XIII. 
CHAPTER  XIV. 
CHAPTER  XV. 
CHAPTER  XVI. 
CHAPTER  XVII. 
CHAPTER  XVIIF. 
CHAPTER  XIX. 


THE  PRINCIPLE  OF  THE  ROOF  AND   GENERAL   DIREC- 
TIONS. 

LAYING  OUT  AND  FRAMING  A  SIMPLE  ROOF. 
HIP  AND  VALLEY  ROOFS. 
ROOFS  OF  IRREGULAR  PLAN, 
SQUARE  PYRAMIDAL  ROOFS. 
To  FRAME  A  PENTAGONAL  ROOF. 
HEXAGONAL  PYRAMIDAL  ROOFS. 
CONICAL  ROOFS. 

To  FRAME  A  CONICAL  ROOF  INTERSECTED  BY  A  PITCHED 
ROOF. 

OCTAGONAL  ROOFS. 

FRAMING  AN  OCTAGONAL  ROOF  OF  GOTHIC  SECTION. 

FRAMING  AN  OCTAGONAL  MOLDED  ROOF. 

FRAMING  AN  OCTAGONAL  ROOF  WITH  CIRCULAR  DOME. 

To  FRAME  A  HIGH-PITCHED  OR  CHURCH  ROOF. 

To  FRAME  A  MANSARD  ROOF. 

HEMISPHERICAL  DOMES. 

To  FRAME  A  CIRCULAR  ELLIPTIC  DOME. 

To  FRAME  AN  ELLIPTIC  DOME  WITH  AN  ELLIPTIC  PLAN. 

To  FRAME  A  CIRCULAR. MOLDED  ROOF. 


CHAPTER  XX.         To  FRAME  A  GOTHIC  SQUARE  EOOF  OF  4  CENTRE  SEC- 
TION. 

CHAPTER  XXT.       To  FRAME  A  TRUSSED  EOOF  OF  MODERATE  SPAN  ON  IHE 
BALLOON  PRINCIPLE. 

CHAPTER  XXII.     To  FRAME  A  ROOF  OF  UNEQUAL  HEIGHTS  OF  PITCHES 
AND  PLATES. 

CHAPTER  XXIII.  To  FRAME  A  HIP  AND  VALLEY  EOOF  OF  UNEQUAL  PITCH. 

CHAPTER  XXIY.  To  FRAME  A  EOOF  OF  UNEQUAL  LENGTHS  OF  EAFTERS. 

CHAPTER  XXY.  To  FRAME  A  EOOF  WITH  PITCHED  RIDGES. 

CHAPTER  XXVI.  To  FRAME  A  ROUND-HOUSE  EOOF. 

CHAPTER  XXVII.  FRAMING  CANTILEVER  EOOFS. 


PREFACE. 


IX  placing  this  little  work  before  the  student  of  Architecture  or  Build- 
ing Construction,  I  would  state  that  it  is  not  intended  for  those 
uneducated  but  for  those  who,  desirous  of  becoming  proficient  in  the 
higher  principles  of  construction,  wish  to  study  and  apply  the  best 
methods  in  actual  daily  practice.  With  the  assurance  to  the  student, 
that  he  will  find  the  contents,  i£ studied,  will  return  him  full  remuneration 
by  his  becoming  more  valuable  on  account  of  his  increased  knowledge,  I 
send  it  forth  confidently.  Tiie  cardboard  models  will  prove  the  accuracy 
of  the  methods  described.  The  articles  being  originally  published  in 
Tke  Carpenter,  are  now  issued  edited  and  revised. 

The  entire  work  is  dedicated  to  my  wife,  by  whose  aid  and  encour- 
agement I  have  been  enabled  to  persevere  and  succeed  in  technical 
principles. 

THE  AUTHOR. 
YORK  CITY,  1896. 


ROOF  FRAMING  MADE  EASY 


CHAPTER  I. 


THE  PRINCIPLE  OF  THE  ROOF  AND  GEN- 
ERAL DIRECTIONS. 
WITH   a  view   of   explaining    the 
principle  of  the  truss  and  its 
practical  application  in  the  con- 
struction of  roofs  and  bridges, 
I  have  commenced  with  this   chapter. 
Let  A  B  and  A  C  be  two  rafters  rest- 
ing together  at  the  ridge  or  point,  as  A. 
Even  by  their  own  weight,  these  two 
rafters  would  have  a  tendency  to  slip  at 
the  points  B  and  C,  and  to  sink  at  A. 
If  a  tie  rod  or  beam  be  stretched  from 
B  to  C,  and  the  rafters,  A  B  and  B  C, 
be  made  stiff  or  rigid,  and  the  tie,  B  C, 
not  liable  to  stretch,  then   A  will  be 
made  a  fixed  point.     This  is  the  ordinary 
roof  of  two  rafters  in  which  the  tie,  B  C, 
is  the  attic  floor  beams,  and  which  form 
may  be  used  for  houses  of  small  span. 


FIG.  1. 

When  the  span  is  wide,  so  wide  in  fact 
that  the  tie,  B  C,  being  unsupported  in 
the  centre,  tends  to  sag  by  reason  of  its 
length,  then  the  conditions  of  stability 
are  injured.  Now  if  from  the  point  or 
peak  A  a  string  or  tie  be  let  down  and 
attached  to  the  middle  of  B  C,  as  D,  it 
will  then  be  impossible  for  B  C  to  bend 
or  sag  down,  as  long  as  A  B  and  B  C  are 
the  same  length .  D  will  be  also  like  a 
stationary  point  if  the  suspension  on  tie 
A  D  be  of  iron  or  wood  and  not  stretch. 
But  the  span  may  be  increased,  01  the 
size  of  the  rafters  A  B  and  A  C  dimin- 
ished until  the  rafters  tend  to  sag,  and 
to  prevent  this,  "struts,"  as  D  E  and  D 
F,  are  set  in,  reaching  from  the  station- 
ary point  D  to  the  middle  of  each  rafter, 
or"  to  the  centre  of  its  length,  as  E  and 


F;  thus  making  E  and  F  stationary 
points,  provided  the  struts  E  D  and  F  D 
remain  their  full  length . 

By  this  means  the  "truss"  or  tie  up, 
the  point  D,  and  the  frame,  A  B  D  C,  is 
a  trussed  frame,  or  in  the  term  applied 
in  carpentry,  a  "truss."  Similarly,  if 
D  C  be  long  its  centre  can  be  suspended 
from  the  fixed  point  E  by  a  suspension 
rod,  as  E  G. 


FIG.  2. 

In  every  truss  there  are  two  principal 
strains  exerted  on  the  pieces.  These  are 
termed  Compression  and  Tension.  For 
this  simple  truss  the  rafters  A  B  and  A 
C  are  in  Compression,  or  being  pushed 
together.  A  D  and  B  C  are  extended, 
or  in  Tension.  Those  which,  are  in  ten- 
sion can  either  be  made  of  wood  (as 
wood  is  very  little  liable  to  stretch)  or 
of  wrought  iron  rods,  but  never  of  ropes, 
or  any  material  likely  to  stretch. 

From  the  above,  the  student  will  un- 
derstand that:  the  rafters,  by  their  not 
being  subject  to  compression  or  crush- 
ing, and  the  tie  rod  or  beam,  not  being 
liable  to  stretch,  or,  in  better  words,  sub- 
ject to  tension,  and  the  suspension  rod 
complete  the  truss,  thus  preventing  the 
sagging  of  the  centre  of  the  tie  beam. 

In  modern  roof  construction,  en- 
gineers, as  a  rule,  use  timber  for  rafters 
and  struts  and  iron  for  tie  and  suspen- 
sion rods;  these  materials  being  light 
and  easily  put  together ;  and  I  am  sure 
many  readers  will  meet  roofs  of  this 
class. 

In  the  ordinary  form  of  house  roof 
shown  at  Fig.  2,  the  rafters  are  in  com- 
pression, the  ties,  or  attic  floor  beams. 


8 


ROOF  FRAMING  MADE  EASY. 


in  tension,  and  the  col- 
lar beam  is  in  compres- 
sion, as  it  takes  the  place 
of  the  struts,  yet  gives 
the  head  room. 


GENERAL  DIRECTIONS. 

Roofs  should  be  laid 
out  to  a  scale  on  a  large 
sheet  of  detail  paper 
or  on  a  drawing-board, 
using  a  lead  pencil  and 
two-foot  rule  or  steel 
square.  The  writer  gen- 
erally uses  either  3  inch 
or  1^  inch  scale ;  if  pos- 
sible, as  it  sometimes  is 
on  small  work,  full  size . 

The  reason  these  are 
the  best  working  scales 
is  because  the  three  inch 
scale  works  as  follows : 

3    inches  =  1  foot 


H 
i 

ir 

i 


=  6  inches 

=  4 
=  2 
=  1 
—     k 
-    t 


The    one   and   a  half 
inch  scale  is  similar  but 
the  divisions  are  not  so 
handy.     For  instance: 
1-|  inches  =  1  foot 
f      4i       =6  inches 
i       "        =  4 
i       '•        =2 

I  ::  i1! 

The  above  two  scales 
are  the  best  working 
scales  with  the  excep- 
tion of  the  half  size 
proposition  which  is  veiy 
simple  and  easily  applied 
thus : 

6    inches  =    1 

5        "       =10 

4  =    8 

3 

2 


foot 
inches 


1 


=  6 

=  4 

=  2 

=  1 


1  ^  t  i 

Tff  —  o 

1  <  <  1 

•T2  7* 

The  foregoing  scales 
are  the  best  for  mechan- 
ics, either  foremen  or  at 
the  works.  The  full 
size  laying  out  is  best 


H 


FIG.  3— PLAN  OF  RAFTERS. 


FIG.  4 — PLAN  AND  LAYOUT  OF  A  SIMPLE  ROOF. 


ROOF  FRAMING  MADE  EASY. 


when  possible.  Whether  the  work  is 
laid  out  to  scale  or  full  size,  the  exact 
measurements  should  always  be  marked 
in  plain  figures  on  every  piece. 

The  figures  on  the  steel  square  for 
marking  cuts  may  be  used  if  desired, 
by  placing  the  square  on  the  scale  draw- 
ing and  noting  the  figures  on  the  blade 
and  tongue. 


CHAPTER  II. 

LAYING  OUT  AND  FRAMING  A  SIMPLE 
ROOF. 

J     ET  A,  B,  C.  D,  Fig.  3,  be  the  plan 

Lof  the  wall  plates.  A  D  a  gabled 
end.  and  B  C  a  hipped  end  of  the 
building.  The  roof  is  12  feet  wide 


inch  rafter  as  shown  on  the  top  of  Fig. 
3,  deduct  half  the  thickness  of  the  ridge, 
half  inch,  from  each  rafter  peak,  cut 
also  notch  out  for  the  cut  on  the  plate . 
All  the  rafters  from  F  to  E  will  be 
framed  thus: 

For  the  hip  rafters,  take  the  distance 
B*  C.  and  transfer  it  to  J.  K,  divide  it 
into  two  parts  6  feet  at  L.  and  square  up 
as  L.  M,  O.  Join  M,  J,  and  M?  K.  Pro- 
duce J,  M,  to  N,  (dotted  line)  and  join 
N,  K.  N,  K,  will  be  the  centre  line 
length  of  the  hip,  and  the  width  may 
now  be  set  off  on  each  side  of  it  in  the 
manner  shown  in  the  diagram. 

With  K  as  centre  and  K,  N  as  radius, 
strike  the  arc  N.  O.  cutting  L,  M  ex- 
tended in  O.  On  L,  K  lay  off  the  jack 
rafters  as  Q.  P,  S,  R,  etc. ;  equally  spaced 


FIG.  5. 


to  the  outside  faces  of  the  wall,  and  the 
rise  or  pitch  4  feet  or  one-third  the  span. 
The  dotted  lines  denote  centre  lines. 

To  lay  out  the  gable  end  produce  the 
center  line  of  the  ridge  E,  I.  F  to  G,  and 
from  F  measure  up  4  feet,  join  G,  A  and 
G,  D.  Now  set  off  on  each  side  of  the 
dotted  line  shown,  the  width  of  the 
rafter  2  inches  on  each  side  for  a  4  inch 
rafter,  and  3  inches  on  each  side  for  a  6 


and  square  to  the  wall  plate.  The 
exact  lengths  of  the  jacks  will  be  to 
the  line  O,  P,  R.  K,  and  their  side  bevel 
will  be  as  P.  The  bottom  notch  will  of 
course  be  as  at  A  or  D ;  K  shows  the 
bottom  notch  for  the  hip  rafters  and  N 
the  peak  cut  or  plumb  cut.  Great  care 
should  be  taken  to  have  the  lines  as 
accurate  as  possible,  so  measurements 
will  be  exact. 


10 


ROOF  FRAMING  MADE  EASY. 


CHAPTER  III. 
HIP  AND  VALLEY  ROOFS. 

THE  next  roof  which  I  produce  is 
one  of  the  hip  and  valley  class,  or 
a  main  rectangular  building,  with 
an  L  or  addition.  A,  B,  C,  F,  D, 
is  the  plan  of  the  building  and  the  out- 
side line  of  the  wall  plates.  The  roof  is 
of  half  pitch  or  square  pitch  as  some 
mechanics  call  it,  which  means  that  the 
height  of  the  roof  is  equal  to  half  the 
width  of  the  house.  The  house  has  two 
gables,  one  on  each  end  of  the  main 
part  with  a  hip  on  the  L,  and  the  inter- 
section of  the  L  roof  with  the  main  roof 
produces  two  valleys.  E,  I,  D,  is  the 
plan  of  the  hip  and  E,  J,  D,  is  the  eleva- 
tion of  it  shown  on  the  elevation  Fig.  6, 
where  the  general  view  of  the  con- 
structed roof  is  shown.  Q,  J,  and  J,  F, 
are  the  valleys  on  the  plan. 


FIG.  6. 

In  framing  this  roof  the  simplest  way 
is  as  follows : 

To  obtain  lengths  and  bevels  of  the 
common  rafter,  produce  the  ridge  line 
G,  J,  H,  to  L  and  K.  Join  A,  K,  and 
K,  Q;  also  B,  L,  and  L,  C.  A,  K,  will 
be  the  neat  length  of  the  common  rafter, 
if  no  ridge  board  is  inserted ;  but  if  there 
be  a  ridge  board,  half  its  thickness  must 
be  sawn  off  the  length  on  the  bevel .  K 
is  the  bevel  for  the  top  or  peak  cut  and 
A,  the  bevel  for  the  cut  on  the  plate. 
Any  ordinary  mind  will  see  the  sim- 
plicity of  this  method. 

For  the  hip  rafters  which  will  stand 
over  the  seats  E,  I.  and  D,  I,  produce 
the  line  D,  I,  to  M,  and  set  off  on  it  the 
height  of  the  pitch  I,  M,  equal  to  K,  G. 
Join  M,  E;  M,  E,  will  be  the  exact 
length  of  the  hip  rafter  required,  and 
the  bevel  at  M,  will  fit  the  top  cut,  and 
that  at  E,  the  plate  cut.  In  regard  to 
the  cuts  for  the  jack  rafters,  which  run 
up  the  hips  and  valleys,  it  might  be  said 
that  the  top  cuts  against  -the  ridges  for 
the  rafters  which  run  up' the  valleys 
have  the  top  cut  the  sameKas  the  com- 


mon rafter  top  cut.  The  bottom  one 
which  nails  against,  can  be  readily  de- 
termined by  the  following  simple 
method:  Produce  the  ridge  line  J,  I,  to 
N,  and  make  D,  N,  and  N,  E,  equal  to 
M,  E,  the  length  of  the  hip,  W,  is  the 
jack  on  its  seat  or  as  it  will  appear  in 
position.  X,  is  the  exact  length  of  it 
from  the  plate  line  to  the  hip,  and  the 
bevel  at  X,  will  be  the  exact  bevel  for 
all  jacks  both  on  hips  and  valleys,  being 
reversed  for  different  sides,  right  and 
left  hand. 

The  plumb  cut  of  the  jacks  will  be  half 
pitch,  or  on  the  steel  square,  12  and  12. 

In  order  to  prove  the  exactness  of  this 
method  of  laying  out  such  a  roof,  we 
will  proceed  to  develop  its  planes  or 
sides. 

As  to  the  rectangular  plane,  A,  B,  G, 
H,  take  a  pair  of  compasses  with  a  pen- 
cil point,  and  with  A,  as  centre,  and 
with  A,  K,  radius,  describe  the  arc  K, 
I;  draw  I,  U,  parellel  to  A,  B,  produce 
G,  A,  to  I.  and  H,  B,  to  U,  this  will  give 

A,  B,  U,  I,  the  exact  covering  of  A,  Gr 
H,  B,  on  the  pitch  C,  K;  A,  K,  being 
the  length  of  the  common  rafter  with 
its  necessary  bevels. 

For  the  plane  J,  H,  C,  F,  produce  B, 
L  to  G',  and  draw  C,  F,  Q,  parallel  to- 

B,  L,  J.  G'.     Make  L.  J,  G',  equal  to  H, 
J,   G.     C,  F,  equal  to  C,  F,  also  F',  Q\ 
equal  to  Q,  F,  make  J,  F,  and  J,  Q, 
equal  to  M,  E,  which  will  complete  the 
plane  and  surface  to  cover  G,  J,  H,  C, 
F.  Q,  on  the  plan. 

For  the  plane  J,  F,  D,  I,  take  D,  as 
centre,  with  D,  F,  radius,  and  describe 
the  quarter  circle  F,  P.  Produce  E,  D, 
to  P,  and  through  P  draw  P,  O,  parallel 
to  D,  N,  also  through  N  draw  N,  O, 
parallel  to  D,  P.  D,  N,  O,  P,  will  be 
the  developed  covering,  and  Q,  R.  S,. 
E,  is  similarly  found. 

B,  L,  C,  and  A,  K,  Q,  are  the  gables. 

Now  if  this  roof  be  laid  out  on  a  piece 
of  thin  wood  or  stiff  Bristol  board  the 
roof  can  be  folded  over  by  cutting  en- 
tirely through  the  following  lines:  Cut 
from  K  to  A.  A  to  I,  I  to  U,  U  to  B,  B 
to  L,  L  to  G',  Q'  to  J',  J'  to  F',  F  to  C,  C 
to  F,  F  to  D,  D  to  P,  P  to  O.  O  to  N.  N  to- 
E,  E  to  S,  S  to  R,  and  R  to  Q.  Also 
make  a  slit  half  way  through  the  thick- 
ness of  the  board,  from  Q  to  A.  A  to  B, 
B  to  C.  C  to  L,  D  to  N,  D  to  E,  and  E  to 
Q.  By  folding  the  sides  or  planes  over, 
the  exact  roof  will  be  seen,  thereby  prov- 
ing the  method. 

The  many  apparently  complex  roofs 
which  are  nowadays  placed  on  frame 
buildings  are  apt  to  discourage  those 
young  mechanics  who  are  ambitious,  so 
in  order  to  simplify  and  bring  them 
within  the  grasp  of  all  I  have  now 


ROOF  FRAMING  MADE  EASY 


UNIVERSITY 


11 


adopted  a  plan  of  roof  of  somewhat  un- 
usual form. 

At  Fig.  7  the  plan  isABCDEFG 
H  I  J  L  and  K,  being  the  plan  of  a  small 
frame  house  costing  about  $2,000.  Fig. 
8  is  an  end  view  or  gable  elevation  show- 
ing the  pitch  is  of  the  common  rafters 
which  we  will  assume  to  be  full  pitch, 
or  12  inches  rise  and  12 
inches  run  on  the  steel 
square.  A  B  is  the  top 
line  of  the  plate  across  the 
bay,  or  across  the  widest 

rrt  of  the  house.  A  K 
the  span  across  the 
main  walls  and  E  J  the 
rise  or  pitch;  therefore 
A  J  will  be  the  length 
of  the  common  rafters 
on  the  plan  Fig  7,  that 
will  be  set  on  the  plate  A 
K  from  N  to  O  on  the 
ridge.  A  G,  Fig.  8,  is  the 
span  across  the  narrowest 
part  of  the  house  or  from 
A  to  B.  Fig.  7,  and  E  M 
is  the  rise  or  pitch,  con- 
sequently A  M  will  be 
the  length  of  the  short 
common  rafters  and  the 
bevels  will  be  as  repre- 
sented at  J  M  and  A. 

Now  to  find  the  lengths 
of  the  hips  and  valleys 
and  bay  window  rafters, 
refer  to  Fig.  7,  and  com- 
mencing at  the  near  val- 
ley C  M  square  up  the 
line  M  R,  make  it  equal 
to  E  M  on  Fig.  7  and  join 
C  R.  OR  will  be  the 
length  of  the  valley  with 
top  and  bottom  bevels  as 
shown.  On  the  seat  of 
the  hips  X  D,  square  up 
the  rise  N  T  equal  to  E  J, 
Fig.  7,  and  join  D  T  for 
length  of  hip,  with  top 
and  plate  bevels  as  at  D 
and  T.  It  will  be  noticed 
that  these  rafters  are 
parallel  on  the*  lay-out 
because  their  seats  are 
parallel,  therefore  they 
must  be  correct ;  the  val- 
ley rafter  L  Q  to  stand 
over  L  P  is  determined  in 
like  manner  also  the  hip 
S  K  to  stand  over  O  K. 

As  I  have  previously  shown  several 
ways  to  obtain  the  lengths  of  jack  raft- 
ers on  half  pitch  roofs  I  will  not  repeat 
this  simple  method  here  but  go  on  and 
give  layout  of  bay  window  timbers 

Referring  again  to  the  engraving  Fig. 
8  we  find  that  the  plate  line  of  the  bay 


C  H  D  is  higher  or  raised  up  4  feet  above, 
the  level  of  the  plate  line  of  the  princi- 
pal or  main  walls  as  A  G  B;  to  find 
lengths  of  rafters  we  go  back  again  to 
Fig.  7 .  Here  on  the  seat  of  the  hip  E  U 
we  proceed  to  square  up  the  rise  U  V 
and  join  E  V,  which  will  be  the  length 
of  the  hip  U  V,  being  equal  to  the  rise 


FIG.  7— PLAN  AND  LAYOUT  OF  ROOF. 


C  J,  Fig.  8.  There  will  be  four  hips 
this  length  to  stand  over  E  U,  F  U,  G 
U,  and  H  U,  on  the  seat  of  the  W  X. 
Square  up  the  rise  X  Y  and  join  W  Y 
for  length  of  valley.  There  will  be  two 
needed,  one  for  each  side.  Jacks  can 
be  found  as  before  described.  Regard- 


ROOF  FRAMIiNG  MADE  EASY. 


ing  the  jack  rafters  reaching  from  the 
valleys  over  W  X  to  the  hips  D  N  and 
O  P,  I  might  state  that  the  bottom  and 
top  cuts  will  be  alike  up  to  the  points  N 
and  O  where  the  hips  join  the  ridge  N 
O.  Against  it  they  will  be  a  square 
cut  on  top  edge  with  the  down  cut  as  at 
J  Fig.  7. 


A 


FIG.  8— PROJECTION  OF  ROOF. 

When  calculating  the  timbers  or  lay- 
ing out  roofs  of  this  description,  too 
much  care  cannot  be  bestowed  in  watch- 
ing the  exact  number  of  rafters  required, 
the  right  and  left  hand  cuts  of  the  bevels 
on  the  jacks,  etc.,  and  the  exactitude  of 
framing  to  the  neat  lengths  required  so 
as  to  prevent  mistakes  or  recutting. 


do  this  I  will  not  illustrate  it  here.) 
This  process  will  give  the  seats  of  the 
hips  as  shown  and  lettered,  with  the 
ahdition  of  a  short  piece  of  ridge  F,  G. 
To  find  the  lengths  and  bevels  of  the 
rafters,  proceed  as  follows: — For  the 
common  rafters  to  range  from  U,  E,  to 
V,  F,  on  the  one  side,  and  from  E,  W, 
to  G,  X,  on  the  other  side ; 
raise  up  the  pitch  G,  P. 
Square  put  from  G  to  X, 
and  join  P,  X  which 
joining  line  will  be  the 
exact  length  of  the  com- 
mon rafter  from  outer 
edge  of  plate  to  centre 
line  of  ridge.  To  obtain 
length  of  hip  rafters 
square  up  from  each  point 
at  the  peaks,  as  E,  H ;  F, 
I.  on  one  side.  Make  E, 
H,  and  F,  I,  each  equal  to 
G,  P;  A,  H,  and  B,  I,  will 
be  the  lengths  of  the 
hip  rafters,  which  will 
E,  and  B,  F.  The  hip 
will  be  set  up  over  the 


CHAPTER  IV. 


ROOFS  OF  IRREGULAR  PLAN. 

THIS  chapter  embraces  a  roof  of  an- 
other and  ratheruncjommonplan, 
and  one  which  will  be  interesting 
to  work  out.     It  is  a  form  of  roof 
which  sometimes  occurs  and  will  prove 
useful. 

A,  B,  C,  D,  Fig.  9,  is  the  plan,  and  it 
will  be  noticed  that  the  side  walls  are 
not  parallel,  or  at  equal  distance  apart 
from  end  to  end,  but  spread  or  widen 
out  from  A  to  B,  and  from  C  to  D,  or  B, 

D,  is  longer  than  A,  C.     Similarly  A,  B, 
is  longer  than  C,  D,  and  not  parallel  to 
C,  D.     For  this  reason  coupled  with  the 
necessity  of  keeping  the  ridge  level  on 
both  sides  a  deck  is  formed  on  the  top, 
or  more  properly  two  ridges  are  needed, 
one  for  each  side,  and  parallel  to  each 
wall  plate;  these  are  shown  as  E,  F,  and 

E,  G. 

The  seats  of  the  hips  as  A,  E,  C,  E,  B, 

F,  and  D,  G,  are  found  by  bisecting  each 
of    the    separate    angles  on    the    plan, 
which  can  be  done  by  taking  any  two 
points  equidistant  from  the  apex  of  the 
angle    as  A.   and  striking  intersecting 
arcs.     (As  every  student  knows  how  to 


rise  over  A 
rafters  which 

seats,  C,  E,  and  D,  G,  are  determined  in 
a  similar  manner.  The  top  and  bottom 
bevels  delineated  at  the  peaks  and  bot- 
toms are  the  top  and  bottom  cuts  of  each, 
and  it  will  be  noticed  that  no  two  bevels 
are  alike,  so  that  each  rafter  must  be 
carefully  laid  out  and  marked  for  each 
particular  corner.  There  will  be  four 
hips  of  different  lengths  and  with  differ  - 
erent  bevels,  so  they  must  be  properly 
framed.  In  regard  to  the  jack  rafters 
they  are  shown  on  the  right  side  spaced 
out  on  the  wall  plate  from  X  to  D, 
against  the  hip,  G,  D.  Their  top 
down  bevel  or  plumb  cut  will  be  the 
same  as  that  at  P,  and  that  at  R  will  be 
the  side  bevel.  Similarly  with  those 
from  D  to  M,  the  plumb  cut  will  be  the 
same  as  P,  but  the  bevel  will  be  that  at 
O. 

In  order  to  develop  the  planes  of  this 
roof,  commence  by  drawing  E.  U,  S, 
from  E,  through  W,  at  right  angles  to 
E,  F,  or  A,  B;  also  draw  F,  V,  T,  par- 
allel to  E,  U,  S.  Make  A,  S,  equal  to 
A,  H,  by  taking  A  as  center  with  radius 
A.  H,  and  striking  the  arc  H,  S. 
Through  S,  draw  S,  T,  parallel  to  A,  B. 
If  a  center  be  taken  at  B,  and  an  arc 
struck  as  I.  T,  N,  it  will  be  found  that 
the  arc  will  pass  through  T.  or  F,  V. 
produced  at  T.  The  surface  A,  S,  T,  B, 
will  cover  the  plan.  A,  E,  F,  B.  on  the 
pitch  E,  H. 

Draw  E,  J.  square  to  A,  C,  and  pro- 
duce to  K.  Sweep  H,  S,  to  K,  and  join 
A,  K,  and  K,  C.  A,  K.  C,  will  be  the 
covering  plane  which  will  cover  over  A, 
E,  C,  on  plan.  For  the  plane  of  A,  E,  G, 


ROOF  FRAMING  MADE  EASY. 


FIG.  9. 


D,  draw  E,  W,  square  to  E,  G,  and  pro- 
duce to  Q.  With  C  as  centre  and  C,  K, 
as  radius,  strike  the  arc  K.  Q;  draw  Q. 
R,  parallel  to  C,  D.  Join  C,  Q,  which 
will  be  the  centre  of  the  hip  rafter  on 
this  side.  Draw  G,  X,  square  to  C.  D, 
and  produce  to  R>  join  R,  D,  C;Q,  R,  D. 
will  be  the  covering  plane  which  will 
cover  over  C,  E,  G,  D,  on  the  pitch 
G,  P. 

Now  draw  G,  M,  and  F,  L,  square  to 
B,   D,   and  produce  them  to  N  and  O. 


A  model  can  be  made  of  this  roof  by 
cutting  out  the  entire  outside  line  of  the 
covering  and  making  a  slit  from  A  to  B, 
from  B  to  D,  from  D  to  C,  from  C  to  A , 
also  from  Q  to  R,  which  being  folded  up 
will  show  the  completed  roof  with  the 
rafters,  cuts  and  bevels  in  position . 


FIG.  10. 

With  D,  as  centre  and  D,  R,  as  radius 
describe  the  arc  R,  O,  also  the  T.  N. 
Join  N.  O,  B;  N,  O,  D,  will  be  the  cov- 
ering of  the  plan  B,  F.  G,  D,  on  the 
pitch  G,  P.  Q,  R,  Y,  Z,  will  be  the 
covering  or  deck,  being  the  same  size  or 
area  as  E,  F,  G. 

At  Fig.  10  will  be  seen  the  elevation, 
or  as  it  will  appear  when  framed,  raised 
and  covered. 


CHAPTER  V. 

SQUARE  PYRAMIDAL  ROOFS. 

DOOF  framing  is  a  study  well  worthy 
the  attention  of  every  student  of 
J[  V  building  construction.  The  roof 
illustrated  and  described  in  this 
chapter  is  one  which  occurs  on  many 
cottages  and  houses  now-a-days.  It  is 
one  of  a  kind  of  tower  roofs  on  a  square 
plan  or  as  they  are  sometimes  termed 
"Pyramidal  roofs."  A,  C,  D,  F,  Fig. 
11,  is  the  projection  of  the  roof  com- 
pleted. A,  C,  D,  B,  Fig.  12,  the  plan  cf 
the  roof  on  the  plates;  AE,  CE.  DE  and 
BE,  being  the  hips  which  form  the 
shape  of  the  roof  or  seats  over  AF,  CF, 
DF,  on  Fig.  11,  stand.  The  fourth  hip 
over  BE,  cannot  be  seen  on  the  projec- 
tion, Fig.  11 . 

In  order  to  find  the  length  of  the  hipp, 
produce  the  line  E,  B.  indefinitely. 
Now  set  off,  measuring  from  E,  the 
height  of  the  peak  to  F,  Fig.  11.  Join 


ROOF  FRAMING  MADE  EASY, 


FIG.  11. 

AF,  Fig.  12,  which  will  be  the  exact 
length  of  either  of  the  four  hips.  In 
framing  this  roof  it  is  best  to  let  two  op- 


posite hips  as  BE,  and  EC,  on  the  same 
line  abut  against  each  other  at  the  peak, 
and  to  cut  off  their  thickness  from  the 
other  two  top  or  peak  cuts,  thus :  If  BE, 
and  EC,  be  each  2  inches  thick  then  1 
inch  will  be  cut  off  the  peak  cuts  of  AE, 
and  DE  which  rest  against  them  at  E. 
This  is  done  in  the  same  manner,  as 
every  top  cut  of  a  rafter  resting  against 
a  ridge  must  have  half  the  thickness  of 
the  ridge  cut  from  each  rafter.  The 
bevel  at  F,  Fig.  12,  is  the  bevel  of  all 
four  top  cuts  and  that  at  A,  the  bevel 
for  the  cuts  on  the  plate. 

Concerning  the  jack  rafters,  the  best 
way  to  determine  their  length  is  to  set 
them  off  the  plate  as  from  A  to  C.  Fig. 
12,  then  to  draw  a  line  as  H,  E,  G, 
through  E,  parallel  to  AC,  or  BD.  With 
A,  as  centre  and  AF,  as  radius  describe 
the  arc  FG,  cutting  the  H,  E,  G,  at  G. 
Join  G,  A,  and  G,  B.  The  triangle,  or 
more  properly  speaking,  the  triangular 
surface  G,  A,  B,  will  be  the  exact 
covering  surface  of  the  roof  plane 
A,  E,  B. 


ROOF  FRAMING  MADE  EASY. 


15 


From  where  the  jack  rafters  come 
against  the  hip  AE,  draw  lines  parallel 
to  E,  G,  and  square  to  A,  B,  cutting  A 
G.  as  shown.  The  lines  reaching  from 
the  plan  line  A,  B,  to  A,  G,  will  be  the 
exact  jack  rafters  and  the  bevel  at  K, 
will  be  the  side  cut  against  the  hip,  with 
the  bevel  at  F,  as  the  vertical  cut,  and 
that  at  K,  the  bottom  or  pla+e  cut. 

The  development  of  the  covering  for 
the  remaining  three  planes  of  the  roof  is 
found  by  drawing  the  line  I,  J, 
through  E,  parallel  to  A,  B,  or  C,  D; 
then  with  B,  as  centre  and  B,  G,  as 
radius  intersecting  E,  J  at  J,  and  joining 
J,  B  and  J,  D ;  a  similar  process  can  be 
gone  through  to  determine  the  points 
H,  and  I.  thus  obtaining  the  four  con- 
vexing  planes. 

To  prove  the  accuracy  of  this  and  the 
two  previous  roof  problems  before  de- 
scribed, or  in  fact  any  roof  problem,  the 
plan    should    invariably    be 
laid  out  to  a  scale,    say  H 
inches  to  1  foot.     On  a  sheet 
of    cardboard    ^  inch   scale 
will  do  if  the  roof  be  very 
large,  then  to  make  a  card-  . 

board  model.     Here  this  can  ' 

be  done  and  when  the  lines 
have  been  laid  down,  as  ju&t   J[j 
described,   the  entire  model 
may  be  made  as  follows: — 
With  a    sharp    pocketknife 
cut  clean  through  the  card-          \ 
board  from  A  to  G,  from  G  to 

B,  from   B  to  J,  from  J  to 
D,  from  D  to  H,   from  H  to 

C,  from  G  to  I.  and  from  I 
to  A.       Next    make    a    slit 
halfway   through  the  card- 
board  from  A  to   B,  from  B 
to  D,  from  D  to  C.  and  from 
C  to  A.     Proceed  to  fold  the 

planes  over  the  seats  till  they  all  join  at 
the  edges,  thereby  making  a  completed 
cardboard  roof  resembling  Fig.  11  with 
the  jacks  and  bevels  in  position,  and 
with  all  the  cuts  fitting  as  they  ought  to. 


houses  built  on  this  plan,  I  think  it  wise 
to  describe  it  as  the  knowledge  is  easily 
carried  and  may  prove  useful . 

Fig.  13  illustrates  the  simplest  and 
most  accurate  method  of.  striking  out  a 
pentagon,  or  five-sided  figure,  one  side 
being  given.  For  example,  if  the  length 
of  one  plate  line  as  E  D,  Fig.  14,  be 
drawn  to  a  scale  on  any  plan,  the  car- 
penter can  very  readily  lay  out  his 
pentagon  full  size  or  half  size,  as  fol- 
lows:—Let  C  E,  Fig.  13,  be  any  line 
equal  to  the  line  E  D,  Fig.  14.  Divide 
C  E,  into  two  parts  at  G,  and  produce 
C  G  E.  Make  E  J,  equal  to  C  E.  and 
with  E,  as  centre  and  radius  E  C,  de- 
scribe the  semi  circle  C  K  L  F  J.  Di- 
vide tho  semi-circle  into  five  equal 
parts  at  the  points  K  L  F  and  M.  From 
the  point  G,  square  up  the  line  G  I. 
Join  E  and  F,  and  bisect  the  joining 
line  E  F,  at  H .  From  H,  square  out, 

A 


CHAPTER  VI. 

To  FRAME  A  PENTAGONAL  ROOF. 

SOME  time  since  the  writer  was  re- 
-quired  to  lay  out  a  pentagonal  or 
five-sided  band  stand  which  had  a 
slate  roof  terminating  in  a  wooden 
finial  at  the  apex.     As  this  roof  is  of  a 
form  rarely  met  with  in  building  con- 
struction,  I   introduce    it    here,    being 
under     the     impression     that    readers 
might   perhaps   have    occasion    to    use 
the  lines  for  such  a  roof.     However,  as 
there  are  pavilions,  pagodas  or  summer 


l<*~  (S  \ 

JL  ~'£~  & 

13 

FIG.  13. 

cutting  the  line  G  I,  at  I,  and  with  I  as 
centre  and  F  as  radius,  describe  the  cir- 
cle A  B  C  D  E  F.  Set  the  compasses  or 
a  rod  to  the  length  C  E,  or  E  F,  and 
space  off  round  the  circle,  also  join  the 
points  together  by  lines  and  complete 
the  pentagon,  as  indicated  by  the  heavy 
black  lines . 

In  order  to  lay  out  the  hip  and  jack 
rafters  for  a  roof  of  this  description, 
proceed  to  Fig.  14,  and  lay  out  the  out- 
side lines  of  the  plates  as  A  B,  B  C,  C  D, 
and  D  E,  also  with  the  compasses,  de- 
scribe the  thickness  of  the  finial  or  boss, 
against  which  the  top  ends  of  the  five 
hip  rafters  rest,  also  lay  out  the  hip 
rafters  as  indicated  in  the  diagram  in 
three  lines;  the  centre  one  being  the 
line  of  the  backing,  and  those  oh  either 
side  the  thickness  of  ths  hip .  By  back- 
ing is  meant  beveling  the  top  edges  of 
the  hip  to  permit  the  roof-boards  or 


16 


ROOF  FRAMING  MADE  EASY. 


sheathing  to  lie  on  the  solid  timber  in- 
stead of  only  on  the  sharp  arris  or  edge 
of  the  rafter.  The  seats  of  the  jack 


centre  or  apex  and  B.  Fig.  14.  Square 
up  from  the  apex  as  X,  equal  in  height 
to  the  pitch  or  rise  of  the  roof.  Join  B 


FIG.  14. 


rafters  may  also  be  laid  down  as  shown. 
To  find  length  of  hip  rafters  join  the 


FIG.  15. 


and  X,  to  obtain  the  length  of  the  hip 
and  its  apex  and  plate  cuts,  seen  in  tho 
diagram.  There  will,  of  course, 
be  five  hip  rafters  this  length 
required.  The  length  of  each 
jack  rafter  may  be  obtained  in  a 
very  simple  way  by  squaring  up 
from  each  jack  where  each  rests 
against  the  hip  and  setting  off 
each  height  of  each  jack,  thus 
determining  the  exact  length  of  B 
Z  C,  being  the  development  of  the 
B  R  C.  The  side  bevel  will  be  as 
Q,  which  must  be  reversed  for 
jack  on  opposite  sides  of  the  hips. 
There  will  be  five  sets  with  a 
right-hand  side  bevel  and  five 
sets  with  a  left-hand  side  bevel. 
Regarding  the  'backing  of  the 
five  hip  rafters,  the  first  thing  to 
be  done  is  to  find  the  desired 
bevel.  This  is  easily  accom 


ROOF  FRAMING  MADE  EASY. 


17 


plished  by  taking  any  point,  as  S,  Fig. 
15.  and  from  S,  drawing  square  to  E  R, 
as  O  P.  From  S.  let  fall  a  line  per- 
pendicular to  E  V,  as  S  T.  With  S 
as  centre  and  S  T  as  radius,  describe  the 
circle  S  T  U  cutting  R  E,  at  U.  Join 
U  P  and  U  9.  O  U  P,  will  be  the  bevel 
of  the  backing  and  a  bevel  may  be  set 
to  one  side  of  the  rafter . 


CHAPTER  VII. 


HEXAGONAL   PYRAMIDAL  ROOFS. 

READERS  will  see  at  Fig.  16  the 
top  and  side  views  of  a  hexagonal 
or  six-sided  roof,  or  one    which 
has  a  wall  plate  running  round 
on  six  walls  as  shown  above,  the  dotted 
lines   representing   the  angle    lines  of 
the  hexagonal  figure.     The  completed 
roof  with  the  boarding  or  tin  on  will 
appear  as  shown  on  lower  sketch. 

In  order  to  frame  this  roof  the  follow- 
ing system  should  be  used : 

At*  Fig.  16  proceed  to  lay  out  on  a 
board  or  paper  to  a  scale  of  1±  or  3 
inches  to  the  foot,  the  plan  of  the  wall 
plates  (on  the  outside  line) .  *A,  B,  C. 
1).  E,  F  ;  and  join  the  points  of  the  in- 
tersections of  the  sides,  as  A  D,  B  E,  and 
C  F  ;  passing  through  the  centre  G. 
This  gives  the  seats  of  the  hip  rafters  A 
G,  B  G,  C  G.  D  G,  E  G  and  F  G  ;  six  in 
all.  To  find  their  exact  length,  square 
up  from  E.  G,  as  G.  J.  Lay  off  also  to 
the  same  scale,  the  exact  height  in  feet 
of  pitch  or  rise  of  the  roof  from  G,  to  J, 
and  join  J,  E,  which  line  will  be  the  ex- 
a'jt  length  of  the  hip  rafter  as  seen  in 
the  diagram  with  the  top  and  bottom 
bevels  necessary  for  the  cuts,  these  be- 
ing given  at  once  without  any  uncer- 
tainty. 

To  find  the  length  of  the  common 
rafter,  to  stand  over  H,  G,  set  off  the 
pitch  G.  I.  on  G,  C,  equal  to  G,  J,  and 
join  H,  I.  for  its  length.  This  rafter  is 
rarely  used  on  roofs  of  this  class,  ex- 
cept when  they  are  of  large  area,  as 
only  the  jacks  are  requisite,  especially 
on  modern  frame  houses  where  they 
seldom  exceed  eight  feet  in  width,  thus 
requiring  short  rafters. 

To  develop  this  roof  take  a  pair  of 
compasses,  and  with  E.  as  centre,  and 
radius  E.  J.  describe  the  arc  J,  M  L, 
Cutting  H.  G,  produced  in  L.  Join  E, 
L,  and  D,  L,  which  will  give  the  trian- 
gle E,  L,  D.  the  covering  over  the  plan 
E.  G,  D,  on  the  pitch  or  rise  G,  J.  Bi- 
s  »ct  or  rather  divide  E,  F,  into  two 
parts  at  Q.  Square  up  from  Q.  cutting 
the  arc  J.  M.  L.  at  M.  Join  M,  E  and 
M,  F.  The  triangle  E,  M,  F.Jwill  lie 


over  E.  G,  F.  The  remaining  four  tri- 
angular developments  or  coverings  can 
be  laid  out  from  the  foregoing  bv 
making  J,  O,  H,  K,  R,  N,  and  S,  P\ 
equal  in  length  to  Q,  M,  or  a  simpler 
method  would  be  to  take  G,  as  centre 
with  G,  M.  as  radius  and  describe  short 
arcs  cutting  O,  K,  N.  and  P,  thus  giv- 
ing the  exact  lengths  at  one  sweep,  and 
insuring  their  being  alike  so  as  to  meet 
at  the  centre  G  when  folded. 


I 

FIG.  16. 

The  side  bevel  at  K,  will  make  the  top 
cuts  on  the  jack  rafters  fitting  against 
the  hips,  the  bottom  cuts  fitting  on  the 
plates  being  the  bevel  at  H. 

Almost  every  mechanic  knows  how  a 
hexagon  or  six-sided  figure  is  struck 
out,  still  in  case  there  should  be  even 
one  student  who  is  at  sea  in  regard  to 
it,  I  repeat  the  method  of  doing  so  here. 
The  diameter  or  length  from  angle  to 
angle  is  usually  given,  or  if  not,  is 
easily  found  by  joining  the  angles  as 
before  described.  Now  to  lay  out  any 


18 


ROOF  FRAMING  MADE  EASY. 


hexagon,  draw  any  line  as  F,  C,  and 
divide  it  into  two  equal  parts  at  G. 
With  G,  centre  and  radius  G,  F,  strike 
the  circle  A,  B,  C,  D,  E,  F.  Now  take 
a  pair  of  dividers  (sharp  points  on  both 
legs)  and  from  C,  with  one  point  on  C, 
space  out  the  six  distances  C,  B,  B,  H, 
A,  F,  F,  E,  E,  D,  and  D,  C.  Draw  the 
lines  as  shown  for  the  outline  of  the 
hexagon. 


modern  houses,  barns,  etc.  The  meth- 
ods to  be  followed  in  this  chapter  are 
very  simple,  so  that  an  ordinary 
mechanic  can  easily  understand  them  if 
he  only  studies  the  diagram  and  text  a 
little. 

Supposing  A,  B,  C,  D,  E,  F,  G,  H,  on 
Fig.  18  to  be  the  plan  or  plate  line  of 
the  roof,  and  O,  L,  the  pitch  or  rise,  it 
can  be  laid  out  as  follows :  To  be  more 


M 


\ 


FIG.  17. 


CHAPTER  VIII. 


CONICAL  ROOFS. 

HAVING  treated  the  usual  forms  of 
roofs  embracing  the  hip  and  val- 
ley principles,  I  will  now  draw 
attention  to  the    proper  laying 
out  and  framing  of  a  roof  on  a  circular 
tower,  as  this  form  occurs  very  often  in 


explicit  I  will  take  it  for  granted  that  a 
carpenter  has  a  roof  to  frame  with  a 
plan  A,  B,  etc . ,  of  6  feet  diameter,  or 
6  feet  from  C  to  G,  and  9  feet  rise,  or 
from  O  to  L  is  9  feet.  Proceed  to  strike 
the  plan  A,  B.  etc.,  either  full  size  or  to 
scale.  It  is  always  better  to  lay  out  full 
size  if  a  floor  or  drawing-board  can  be 
found  big  enough  to  do  it,  but  if  not, 


ROOF  FRAMING  MADE  EASY. 


19 


half  size  or  a  scale  of  3  inches  or  1^ 
inches  to  the  foot  may  be  used. 

Having  struck  the  circle,  draw  centre 
lines  for  the  rafters  A  E,  B  F,  C  G,  and 
D  H,  and  set  off  the  thickness  of  the 
rafters  as  they  show  on  the  plan .  Next 
draw  any  straight  line  as  J  K,  the  same 
length  as  C  G;  raise  up  the  centre  line 
O  L,  the  height  of  the  pitch,  and  join  L 
K,  which  will  be  the  length  of  the  raft- 
ers to  stand  over  A  I,  B  I,  C  I,  D  I,  E  I, 
F  I,  and  G  I  and  the  top  and  bottom 
cuts  will  be  directly  given;  as  at  L  and 
J,  L  M  and  L  N  are  the  rafters  I  D  and 


may  be  determined  by  striking  out  the 
sweeps  shown  on  the  plan,  1  1,  2  2,  3  3, 
4  4,  and  5  5.  It  will  be  noticed  that  this 
roof  will  require  8  circular  pieces  for 
each  row,  or  40  sweeps  in  all .  One  pat- 
tern will  do  for  each  sweep  and  the  re- 
maining 8  needed  can  be  marked  from 
each  pattern. 

Fig.  19  will  convey  a  better  idea  of 
the  constructed  roof,  as  this  illustration 
represents  each  stud,  plate,  rafter  and 
sweep  in  its  fixed  position,  with  the 
covering  boards  nailed  on  half  way 
round. 


FIG.  18. 


I  E  placed  in  position  and  L  O  is  the 
rafter  E  I  in  position.  By  referring  to 
Fig.  19  the  rafters  B  I,  A  I  and  H  I  will 
be  seen  at  the  rear  of  the  figure. 

If  the  roof  is  t.c  be  boarded  vertically, 
horizontal  strips  or  sweeps  will  require 
to  be  sawn  out  and  nailed  in,  in  the  man- 
ner represented  in  both  Figs.  18  and  19. 
To  do  this  properly,  divide  the  height 
from  O  to  L  in  Fig.  18  and  draw  the  lines 
representing  the  sweeps  as  1  1 ,  2  2.  3  3, 
4  4,  and  5  5.  The  neat  length,  and  the 
cuts  to  fit  against  the  sides  of  the  rafters 


In  order  to  find  the  exact  shape  and 
levels  for  the  covering  boards,  a  very 
simple  method  is  used,  thus :  Take  a  pair 
of  compasses,  or  a  trammel  rod,  and 
with  L  as  centre,  and  L  P  as  radius,  de- 
scribe the  arcs  J  P  and  K  Q.  Join  L  P 
and  L  Q,  now  divide  the  half  circle  A, 
B,  C,  D,  E,  into  12  equal  spaces  on  J.  P, 
with  a  pair  of  compasses,  and  join  the 
division  marks  on  J  P  with  L  This 
will  give  12  tapering  boards  and  the 
bevel  at  X  on  the  plan  will  be  the  bevel 
of  the  jointed  edges.  As  twelve  boards 


FIG.  19 


ROOF  FRAMING  MADE  EASY. 


21 


will  be  needed  for  half  the  plan,  twenty- 
four  will  have  to  be  cut  out  for  the 
other  half,  so  it  will  be  seen  that  if  the 
sweep  or  arc  J  P  goes  round  from  A  B 
to  E,  the  sweep  K  Q  will  go  round  H, 
K,  G,  etc.,  to  E.  The  diminishing  lines 
from  the  point  L  to  the  line  J  P  are  the 
inside  lines  of  the  joints  of  the  boards 
shown  also  in  Fig.  19. 

In  order  to  prove  the  rectitude  of  the 
foregoing,  a  model  can  be  made  by 
drawing  the  roof  to  scale  on  cardboard, 
and  then  cutting  out  the  figures  from  L 
to  J,  from  J  to  K,  and  from  K  to  L. 
Also  cut  out  the  figures  L  P  S,  and  L  Q 
K.  Now  if  L  S  K  be  stood  up  over  A, 
E,  B,  F,  etc.,  it  will  be  seen  to  fit  over 
each. 

In  a  similar  way  the  figure  L  J  P  will 
bend  around  ABODE  with  the  peak  L 
over  the  point  I  and  the  line  J  P  around 
ABODE.  In  a  like  manner  K  Q  will 
bend  around  A  H  G  F  E  and  L  will  lie 
over  I,  thus  proving  the  correctness  of 
the  methods  followed.  Care  must  be 
taken  to  allow  for  the  intervening  raft- 
ers when  framing  the  peak  cuts  of  the 
rafters. 


To  find  the  lengths  of  jack  rafters, 
proceed  to  Fig.  21 ,  and  lay  out  the  ridge 
and  valley  rafter  as  before.  With  F  as 


To 


CHAPTER  IX. 

FRAME  A    CONICAL    ROOF    INTER- 
SECTED BY  A  PITCHED  ROOF. 


AS  this  is  a  roof  which  occurs  in 
many  cases,  especially  in  railroad 
work,  it  will  be  found  both  inter- 
esting and  useful. 

Let  A  E  F  B  V,  Fig.  20,  be  the  plan 
or  wall  plate  of  the  conical  dome,  and 
A  D  B,  the  diameter,  also  D  0,  the  rise 
or  pitch.  Join  A  C,  to  obtain  the 
lengths  of  the  common  rafters  which 
will  radiate  from  the  centre  C,  round 
the  circular  plate  A  E  F  B  V,  with  the 
top  and  bottom  bevels  as  represented  at 
C  and  A. 

On  account  of  the  pitched  roof  C  H  F, 
the  gable  end  of  which  is  G  I  H,  with 
pitch  J  I,  equal  in  height  to  D  C,  inter- 
secting or  cutting  into  the  conical  dome, 
there  will  be  a  valley  rafter.  The  seat 
of  this  valley  will  be  D  F.  because  J  I, 
being  equal^to  C  D,  the  ridge  J  E,  will 
be  the  same  height  as  the  conical  apex 
or  peak  D . 

To  obtain  the  length  of  the  valley 
rafter,  square  up  from  D,  and  with  D, 
as  centre  and  D  C,  as  radius,  cut  off  the 
length  D  K,  equal  to  D  C.  Join  F  K. 
F  K,  will  be  the  length  of  the  valley, 
and  as  D  B.  is  equal  to  D  F,  and  the 
pitches  D  C.  and  D  K.  are  equal,  there- 
fore the  valley  will  be  the  same  length 
as  common  rafter. 


*FiG.  21. 

centre,  and  F  K,  as  radius,  describe  the 
curve  K  Z,  cutting  the  ridge  at  Z.  Join 
F  Z.  The  lengths  of  the  jacks  will  be  as 
shown  on  the  left  side  of  the  ridge. 

The  final  process  is  to  determine  the 
shape  of  the  covering  or  roof  boards 
which  are  laid  horizontally.  To  do  this 
take  C,  Fig.  20,  as  center,  and  with 
equal  spaces  up  the  common  rafter  as 
P  Q  R  S,  strike  the  parallel  curves  P  T, 
Q  U,  R  V,  and  S  W.  The  exact  length 
of  the  boards  is  found  by  dividing  F  B 
into  five  equal  parts  and  setting  them 
off  on  B  X.  Join  C  X,  to  determine  the 
length  of  all  to  the  apex.  A  very  suc- 
cessful cardboard  model  can  be  made  of 
this  roof. 


CHAPTER   X. 


OCTAGONAL  ROOFS. 

AT  Fig.  22,  A  B  C  D  E  F  G  H  is  the 
plan  of  the  octagonal  roof.     I  is 
the  centre  or  peak.      A  I,  B  I, 
etc. ,  are  the  seats  of  the  hips.  L  J 
is  the  length  of  the  common  rafters.    B 
K  the  exact  length  of  the  hip  rafters . 

To  find  side  bevel  of  hips,  produce  N 
I  to  M,  and  make  B  M  equal  to  B  K ; 
join  M  B  and  M  A.  The  bevel  at  M  will 
be  the  side  bevel  across  the  top  edges  of 
the  rafters,  and  the  bevej 


ROOF  FRAMING  MADE  EASY. 


FIG.  20— LAYING  OUT  OF  ROOF. 


ROOF  FRAMING  MADE  EASY. 


23 


the  hips  will  be  the  bevel  across  the  top 

edges  of  the  jacks,  right  and  left  hand. 

Proceed  to  Fig.  23,  and  to  obtain  side 

bevel  of  octagon  hip  rafters,  on  B  D, 


the  seat  of  the  hip,  raise  up  the  pitch  D 
E.  join  E  B  for  length  of  hip.  To  ob- 
tain side  bevel  of  jacks,  take  B  as  centre 
and  B  E  as  radius,  describe  arc  E  F  and 


FIG,  23. 

join  F  and  B.  Produce  line  of  jacks  to 
meet  B  F,  and  the  bevel  at  G  is  the  side 
bevel  across  top  of  jacks,  applied  right 
and  left,  and  on  right  and  left  sides  of 
hip. 


CHAPTER  XI. 

FRAMING    AN    OCTAGONAL    ROOF 
GOTHIC  SECTION. 


OF 


AS   all    are   interested    in  unusual 
problems    in    carpentry,   I  have 
pleasure  in  laying  before  them  in 
this  chapter  one  which  I  solved 
and  which  is  worth  studying  out .  It  was 
erected  on  a  cupola  of  a  large  institu- 
tion building  in  thefcity  of  New  York, 
and  is  to-day  standing  complete  accord- 
ing to  the  architect's  design . 


FIG.  24. 

A,  B,  C,  D,  E,  F,  G,  H,  Fig.  24,  was 
the  plan  of  the  cupola  or  lantern,  eight- 
sided  in  shape  as  will  be  seen,  Its  ele- 
vation was  as  represented  in  Fig.  25, 
and  its  section  was  a  gothic  of  the 
equilateral  form,  as  G  6,  D  6,  Fig.  25,  F 
6,  and  E  6,  were  the  hip  lines  of  the  oc- 
tagonal plan  to  stand  over  on  Fig.  24, 
the  seats  F  6,  and  E  6.  The  radius  of 
the  gothic  was  as  shown  on  the  eleva- 
tion, and  from  this  we  will  proceed  to 
lay  out  the  roof  and  and  get  the  curves 
for  the  timbers. 

From  the  points  T,  U,  V,  W,  X,  draw 
lines  square  to  Q  6',  as  IL,  UM.  VN, 
WI,  X.  From  the  space  points  on  the 
line  QZ,  make  the  dotted  lines  equal  in 
length  individually  to  TL,  UM,  VN, 
WI,  X;  and  draw  through  the  points 
the  curve  Z,  Y,  G.  Produce  NS,  and 
WR  to  Y  and  Y',  and  the  lines  SY'  and 
RY  will  denote  the  curved  jack  rafters. 
The  bevel  at  Y,  is  that  which  will  fit 
against  the  side  of  the  hip  rafter  as  the 
development  G,  Z,  Q,  will  fold  and 
stand  over  the  G  6',  Q.  The  curve  of 
the  jacks  will  be  the  same  as  G  6,  Fig. 
24,  and  struck  from  the  same  radius. 
This  will  be  readily  understood  by  an 


24 


ROOF  FRAMING  MADE  EASY. 


examination  of  the  diagram,  Fig.  26. 
The  bevel  A  6,  Fig.  25,  will  be  the  plumb 
cut  of  the  jack  rafters. 


Also,  draw  level  lines  from  the  points  1, 
2,  3,  4,  5,  on  6',  6,  cutting  the  plumb 
lines  from  G',  6',  at  the  points  1',  2',  3', 
4',  5',  6'.  Draw  the  curve  G  1,  etc.. 
through  these  points  and  this  curve  will 
be  the  exact  shape  of  the  hip  rafter  re- 
quired to  stand  over  the  eight  seats  seen 
on  Fig.  24. 

For  the  jacks  divide  the  plate  G  F. 
Fig.  26,  into  six  equal  parts  and  draw 
lines  square  to  the  plate  for  the  seats  of 
the  jacks,  as  will  be  seen  from  A  to  H, 
Fig.  24.  These  will  join  with  the  lines 
2  U,  4  W,  at  the  points  U  and  W  on  the 
line  G'  6'.  Produce  them  indefinitely 
outside  G',  F'.  Now  take  the  divisions 
G'  7',  Fig.  24,  and  set  them  off  on  the 
line  Q  Z,  Fig.  26,  and  draw  lines  square 
tcQZ. 


FIG.  25. 

In  order  to  find  the  length  and  curve 
of  the  hip  rafters  which  will  stand  over 
the  seats  on  Fig.  24,  A  6,  B  6,  C  6.  D  6, 
E  6,  F  6,  G  6,  H6,  proceed  as  follows  • 
Take  any  octagonal  triangle  as  G  6  F, 
Fig.  24,  and  lay  it  off  as  G'  6'  F',  Fig. 
26,  G  6,  being  a  level  line.  From  6' 
raise  up  a  plumb  line  as  6',  6.  Next  di- 
vide the  gothic  sweep  on  Fig.  24,  G  6, 
into  six  equal  parts,  as  1,  2,  3,  4.  5,  6, 
and  carry  these  over  to  the  centre  line 
6',  6,  by  horizontal  or  level  lines  as  indi- 
cated. Transfer  these  to  6',  6,  Fig.  26. 
Next  divide  the  line  G'  6',  into  six  equal 
parts,  as  T,  U,  V,  W,  X,  and  from  the 
points  of  division  raise  up  plumb  lines. 


FIG    26. 


ROOF  FRAMING  MADE  EASY. 


CHAPTER  XII. 

FRAMING  AN  OCTAGONAL  MOLDED  ROOF. 

THE  molded  roof  which  I  propose  to 
treat  in  this  chapter  is  one  which 
may  not  be  familiar  to  readers  and 
may    seem    difficult    to  lay  out. 
Various  methods  have  been  put  forward 


FiG.  27. 

for  the    purpose  of  getting    the  exact 
cuts,  etc.,  for  these  roofs,  but  there  have 


been  none  so  far  sufficiently  intelligible 
to  apply  practically.  I  have,  therefore^ 
worked  out  one  of  the  most  usual  forms 
for  the  benefit  of  the  trade  at  large. 

The  first  roof  is  a  regular  "ogee" 
molded  tower  roof  on  an  octagonal  or 
eight-sided  plan.  or.  in  other  words,  the 
plate  is  eight-sided,  as  represented  at 

^  ~7          ^ 

7! 


FIG.  28. 

Fig.  29,  where  the  plan  of  the  rafters  is 
denoted,  including  both  hips  and  jacks. 


Fie.  29 


26 


ROOF  FRAMING  MADE  EASY. 


C,  D,  E,  F,  G,  H,  I  and  J  is  the  eight- 
sided  plate,  and  eight  sides  have  a 
molded  plane  terminating  in  a  point  at 
L,  shown  in  the  layout,  Fig.  30. 

As  there  may  perhaps  be  some  readers 
who  are  not  entirely  familiar  with  the 
proper  ways  of  making  an  eight-sided 
figure  or  octagon,  I  will  explain  this 
here.  Let  a,  b,  Fig.  27,  be  one  side  of 
the  octagon,  say  4  feet  long,  it  is  re- 
quired to  construct  the  full  octagon  8 
feet  6  inches  wide.  To  do  this:  With 
the  steel  square  or  bevel,  draw  a-d  and 


b-c  on  a  miter,  and  make  each  4  feet 
long ;  then  from  c  and  d,  draw  c,  e  and 
d,  h,  square  to  a,  b.  Next  from  e  and 
h,  draw  e,  f  and  h,  g,  op.  a  miter  of  45 
degrees,  and  make  each  4  feet  long;  join 
g  and  /,  to  complete  the  figure.  This 
alone  is  one  way  to  do  it,  and  a  very 
simple  one.  Fig.  28  shows  another  way : 
Let  a  d,  d  c  and  c  &  be  any  square,  say 
8  feet  6  inches  wide.  Draw  the  diago- 
nals from  corner  to  corner,  as  a  c  and  b 
d,  cutting  in  e.  Now  with  the  com- 
passes set  to  e  c  mark  the  sides  at  J  and 


FIG.  80.— LAYOUT  OF  ROOF.    One-half  inch  scale. 


ROOF  FRAMING  MADE  EASY. 


27 


K,  also  at  h  f,  etc.  Join  these  points 
and  the  eight-sided  figure  will  be  given, 
as  shown  by  the  heavy  black  lines  in 
the  engraving. 

By  either  of  the  above  methods  the 
plate  line,  C,  D,  E,  F,  G,  H,  I  and  J  of 
the  plan,  Fig.  29,  may  be  exactly  laid 
out.  or  if  the  cuts  or  octagon  mitres  are 
to  be  found,  the  figures  7  and  17  on  the 
steel  square  will  give  the  cut.  The 
writer  prefers,  however,  to  lay  out  roofs 
of  this  character  full  size,  on  an  ex- 
temporized floor  or  drawing-board  and 
to  strike  out  the  rafters  also  full  size 
with  a  trammel  rod,  a  bradawl  and  a 
pencil.  K,  A,  B,  L,  Fig.  30.  is  the  pro- 
file of  the  roof,  K  A  and  K  B  being  jack 
rafters,  which  will  stand  over 
those  marked  on  the  plan 
above  ;  A  corresponding  to  A 
above,  and  B  to  B  above.  The  * 
bevel  at  X.  is  the  side  bevel  of 
the  jacks  fitting  against  the 
hips,  right  and  left.  The  lay- 
out will  explain  this  very 
clearly. 

To  find  the  exact  shape  of 
the  hip  curve,  as  P  10',  draw 
O  10',  the  seat  of  one  octagon 
angle  or  hip  rafter,  and  from 
O  draw  O  P  square  from  O  to 
10'.  See  Fig.  30.  Divide  the 
"ogee  "  line  L  10  above  into  10 
equal  parts  with  the  compasses 
in  the  manner  shown,  com- 
mencing at  L.  Draw  lines 
from  the  dividing  points, 
plumb  to  the  plate  or  spring 
line  K,  O  10.  and  produce  these 
lines  till  they  cut  the  hip  seat 
O  10',  as  P,  Q,  R,  S,  T,  U,  V, 
W.  then  from  the  points  where 
they  cut  draw  lines  down,  P  1, 
Q  2.  etc.  Finally,  make  the 
heights  of  these  lines  equal 
to  the  heights  on  the  regular 
"ogee"  roof  above,  and  trace 
the  curve  marked  "  Outline  of 
Hip"  for  a  pattern  rafter,  for  all 
the  eight  hip  rafters  required. 

As  I  have  laid  this  roof  out  to  a  scale 
of  a  half  an  inch  to  the  foot,  students 
should  have  no  difficulty  in  reproducing 
it  as  shown. 

Readers  will  find  in  the  sketch,  Fig.  31, 
a  very  simple  method  of  finding  the  side 
cuts  of  the  jack  rafters.  To  square 
across  from  the  side  of  the  rafter  where 
the  thickness  of  the  jacks  rest  against 
it  as  shown  here,  and  to  join  the  oppo- 
site corners  for  the  bevel  as  1-2  and  3-4. 
Another  way  to  find  this  cut  is  to  de- 
velop the  roof  in  the  way  I  have  de- 
scribed in  previous  chapters.  And  still 
another  is  to  apply  the  steel  square  on 
the  bottom  edge,  using  the  ordinary 


octagon  jack  rafter  cut.  The  plumb  cut 
being  always  the  same.  As  the  jacks 
and  common  rafters  have  the  same  pro- 
file they  must  coincide. 


CHAPTER  XIII. 

FRAMING  AX  OCTAGONAL  ROOF  WITH  A 
CIRCULAR  DOME. 

AT  Fig.  32,  let  A  B  C  D  E  F  G  H,  be 
the  plan  of  the  wall  plates  of  the 
main  octagonal  roof  and  H  O. 
G  O.  G  N,  E  N,  F  M,  E  M,  E  L,  D 
L,  DK,  CK,  CV,BV,BJ,  AJ,  Aland 
H  I,  the  seats  of  the  octagonal  hip  raft- 


FIG.  31. 

ers.  The  intervening  planes  between 
the  hips  will  be  circular  surfaces  as  O  N. 
and  the  rafters,  if  cut  in  horizontally  as 
shown  in  the  engraving,  will  be  curved 
on  the  outer  edge  and  each  sawn  to  a 
different  radius  using  the  centre  of  the 
octagonal  plan  and  upper  circular  plate 
J  N  K  L  M  N  U  O  I.  as  a  fixed  centre 
and  increasing  the  radius  for  each  sweep 
as  they  go  down  on  the  pitch  in  the 
manner  seen  in  Fig.  33,  where  the  sweeps 
are  represented  cut  in  between  two  hip 
rafters,  the  bottom  cuts  of  which  rest 
at  the  angle  of  hip;  this  will  also  be 
seen  on  the  plan  Fig.  32,  as  G  O  and 
G  N.  The  unoer  ends  or  cuts  of  the 


28 


ROOF  FRAMING  MADE  EASY. 


octagonal  hips  are  cut  to,  and  notched 
under,  the  upper  circular  plate  which 
carries  the  studding,  forming  the  drum 
of  the  dome. 

Concerning  the  length  of  the  hips, 
jacks,  and  common  rafters,  readers  will 
find  the  simplest  method  of  determining 
their  length  to  be  that  shown  on  the 


M  Q,  and  join  P  Q,  which  will  be  the 
length  of  the  common  rafter  to  stand 
over  the  seat  3  N.  For  the  jacks  from 
P,  on  the  line  P  M,  set  off  the  distances 
from  the  line  of  the  outside  of  the  plate 
as  1,  2,  or  4  and  5  to  the  point  where 
each  comes  against  the  side  of  the  seat 
of  the  hips  G  N,  and  F  N,  as  P  Y,  P.  W. 


FIG.  32. 


diagram  Fig.  32.  To  obtain  the  length 
of  the  main  hips  as  G  N,  and  so  on,  lay 
off  the  seat  F  M,  and  square  up  from  M, 
as  M  R.  Join  R  F,  which  will  be  the 
exact  length  of  the  hip,  to  scale,  and  R, 
and  E,  will  be  the  top  and  bottom  bevels. 
For  the  common  rafter  as  3  N,  divide  F 
E  into  two  equal  parts  at  P,  square  up 
from  P  as  P  M,  and  from  M  square  up  as 


From  the  points  W,  and  Y,  square  out 
till  each  line  cuts  the  line  P  Q,  at  X  and 
Z ;  P  X  and  P  Z,  will  be  the  exact  length 
of  each  jack  to  the  longest  point. 

The  curved  stud  for  the  drum  U  V,  in 
Fig.  32,  shows  how  the  design  of  the 
roof  may  be  made  more  graceful  by  in- 
troducing curved  studs  instead  of  the 
straight  studs  seen  in  Fig.  33.  S  T 


ROOF  FRAMING  MADE  EASY. 


shows  the  O  G  rafters  of  the  top  or  dome, 
and  with  its  rise  and  rim.  A'  B  C  on 
the  top  side  of  the  engraving  illustrates 
how  this  roof  may  be  developed  in  the 
way  I  have  illustrated  and  explained  in 
the  previous  chapters,  as  I  have  by  slow 
degrees  led  up  from  the  simplest  to 
intricate  roofs  and  their  framing. 


CHAPTER  XIV. 

To  FRAME  A  HIGH  PITCHED  OR  CHURCH 
ROOF. 

AT  Fig.  34  let  A.  B,  C,  D,  E,  F,  G.  H, 
I,  J,  K  and  L  be  the  plan  of  the 
wall  plates       Around  to  B  will 
be  a  circular  end.     B  Y  the  pitch 
or  length  of  common  rafter  which  will 
space  along  the  plate  from  B  to  C  and 
from  A  to  L.    The  bevel  at  Y  will  be  the 


length  which  will  be  found  to  be  the 
same  length  as  B  Y. 

C  P,  F  P,  L  P  and  I  P  are  the  seats  of 
the  valley  rafters  with  the  jacks  which 
will  fit  against  all  four.  I  have  drawn 
.  these  on  one  side  only  as  the  other  three 
are  duplicate  rafters  with  the  cuts  re- 
versed. The  top  cut  is  the  same  as  Y, 
and  the  bottom  side  cut  as  W,  which 
may  be  found  by  developing  the  roof. 
Z  is  the  top  cut  of  the  valley  found  by 
raising  up  the  pitch  P  Z  equal  to  X  Y 
and  joining  Z  I  and  Z  C,  and  bevel  at  C 
the  bottom  cut  of  valleys . 

In  order  to  develop  the  planes  of  the 
roof  produce  the  line  C  T  B  to  any 
length.  Produce  A  X  B  to  N  and  with 
a  pair  of  compasses  strike  the  arc  N  Y 
cutting  B  N  at  N,  through  N  draw  N  U 
R  parallel  to  C  T  B  and  produce  S  T  to 


FIG.  33. 


one  required  for  the  top  cut  against  the 
ridge  and  that  at  B  the  bevel  for  and  on 
the  wall  plate.  Similar  rafters  will 
require  to  be  cut  for  the  semi-circular 
end  and  they  will  be  spaced  out  equally 
round  it  as  I  have  drawn  them  half  way 
round  from  B  to  8.  On  account  of  the 
fitting  the  top  or  peak  ends  of  these 
rafters  where  they  group  at  the  top  it  is 
advisable  to  insert  a  circular  boss  or 
block  to  fit  them  against;  the  half  thick- 
ness of  this  block  must  be  cut  from  the 
ends  of  the  rafters  on  the  plumb  cut. 
This  is  shown  at  X  in  the  engraving. 
The  ridge  X  Y  will  also  require  to  be 
fitted  to  it  and  the  common  side  rafters 
A  X  and  B  X.  S  T  is  the  common  rafter 
square  to  the  plate  and  T  U  its  exact 


U,  also  draw  P  through  Q  to  R,  and  set 
off  the  valley  and  jacks  in  the  manner 
shown .  Next  set  a  pair  of  dividers  to 
one  of  the  spaces  round  B  8  and  set  off 
the  eight  equal  spaces  from  B  to  O, 
Join  NO.  If  the  whole  diagram  be  laid 
ouf  on  a  sheet  of  Bristol  or  cardboard  a 
model  may  be  made  and  the  system 
proven  by  cutting  entirely  the  card- 
board with  a  penknife  or  chisel  from  A 
to  B,  thence  to  O,  then  to  N,  N  to  R.  R 
to  P,  P  to  C  and  so  on  as  before  de- 
scribed. The  shape  of  the  covering 
boards  as  may  be  determined  by  taking 
Y,  as  centre  and  with  length  YA  strik- 
ing the  sweep  Y  M,  then  setting  off  on 
Y  M.  16  spaces  each  equal  in  length  to 
1,  2,  etc. 


30 


ROOF  FRAMING  MADE  EASY. 


FIG.  34 — LAYOUT  OF  A  HIGH  PITCHED  ROOF. 


CHAPTER  XV. 

To  FRAME  A  MANSARD  ROOF. 

BEFORE    commencing  to    describe 
the  proper  methods  to  follow  in 
framing  and  raising  a  Mansard 
roof.  I  will  first  explain  what  a 
Mansard  roof  is.     This  form  of  roof  de- 
rived its  name  from  being  constantly 
used  by  one  Francis  Mansard,  an  archi- 
tect who  died  in  France  in  the  year  1666. 
He  was  not,  as  is  generally  supposed,  its 
inventor,  as  the  idea  had  been  previous- 


ly adopted  by  such  men  as  Segallo  and 
Michael  Angelo,  in  Italy. 

The  principal  reason  for  the  use  of  the 
Mansard  form  is  to  lessen  the  excessive 
height  of  a  roof  without  resorting  to  a 
truss,  and  to  obtain  room  space  in  the 
roof  itself. 

To  describe  or  lay  out  a  true  Mansard 
roof,  at  Fig,  35,  let  C  F,  be  the  true 
height  of  the  roof  equal  to  half  the 
width  on  the  plate  line  C  B.  Draw  D  E, 
parallel  to  A  B,  and  make  D  F,  and  F  E, 
equal  to  A  C,  and  C  B.  Join  A  D.  pnd 
E  B.  Divide  D  F,  and  F  E,  into  three 
equal  parts  and  join  A  B,  and  B  D. 
Make  F  G,  equal  to  d  E.  and  join  b  G 

D 


FIG.  35— LAYOUT  OF  A  TRUE  MANSARD 
ROOF. 


FIG.  36 — LAYOUT  OF  A  MANSARD 
OR  CURB  ROOF. 


ROOF  FRAMING  MADE  EASY. 


and  G  D,  thus  obtaining  the  true  form 
of  the  Mansard  roof. 

At  Fig.  36  another  way  to  describe 
this  roof  is  shown,  and  this  resembles 
more  the  old  colonial,  or  what  is  called 
the  American  curb  roof.  To  describe 


FIG.  37— CROSS  SECTION  OF  ROOF. 


it  strike  the  semi-circle  A  E  D  F  B, 
from  the  centre  C,  with  C  D,  as  radius . 
Divide  the  semi  circle  into  4  equal  parts 
at  E  D,  and  F,  and  join  A  E,  E  D,  D  F, 
and  F  B,  which  will  give  the  proportion- 
al form  of  the  roof. 

Fig.  38  will  give  readers  a  full  concep- 
tion of  the  framing  timbers  of  a  Mansard 
roof  as  they  will  appear  when  raised. 
They  consist  of  the  usual  wall  plate  and 
an  upper  plate  which  is  supported  by 
the  flaring  or  sloping  side  rafters  which 


FIG.  40 — To  FIND  LENGTH  OF  MANSARD 
HIP. 

form  the  Mansard  chamber  or  attic 
within.  Reference  to  the  cross-section, 
Fig.  37,  will  make  it  clearer  to  the 
mechanic,  as  A,  is  the  wall  plate,  E,  the 
upper  or  Mansard  plate  supported  by  the 
Mansard  or  flaring  rafters  C,  which 
flares  2  feet  off  the  perpendicular.  D,  is 


FIG.  41. 

the  deck  or  upper  rafters,  and  B,  a  tie  or 
ceiling  beam  which  gives  a  good  attic 
room.  Half  the  roof  only,  namely,  the 
left  side,  is  shown  in  this  cross-section, 
Fig.  37. 


1 


sotrcJ 


FIG.  38— ELEVATION  OF  FRAMING. 


ROOF  FRAMING  MADE  EASY. 


FIG.  39— PLAN  OF  MANSARD  RAFTERS. 


A  comparison  between  the  plan  Fig. 
39.  and  the  elevation  and  cross  section 
will  make  clear  the  full  construction  of 
the  roof  and  enable  any  mechanic  to  lay 
out,  frame  and  raise  roofs  of  this  class. 
The  elevation  and  plan  show  one  end 
(the  right)  hipped  and  the  other  (the 
left)  gabled.  In  order  to  determine  the 
exact  length  of  the  Mansard  hip  rafter, 
the  method  is  illustrated  in  Fig  40.  It 
is  simply  to  raise  up  on  the  seat  X  Z.  of 
the  hip  the  height  of  the  pitch  9  feet 
and  6  inches  and  to  join  this  height 
with  Z. 

The  deck  or  upper  rafters  are  framed 
in  the  way  I  previously  described.  Fig. 
41  represents  the  proper  shape  to  frame 
the  top  cuts  of  Mansard  rafters  to  pre- 
vent their  slipping  under  the  upper 
plate. 

CHAPTER  XVI. 

HEMISPHERICAL  DOMES. 

THE  roof  presented  to  readers  of  this 
chapter    is   one  well  worthy  of 
careful  study  and  working  out. 
It  is  of  a  kind  which  occurs  on 
many  houses  now-a-days  on  the  tops  of 
towers  for  domes,  etc.     I  should  there- 
fore recommend  that  those  who  have 
leisure  time  work  it  out  on  a  board  to  a 
large  scale . 

A,  B,  C,  D,  E,  F,  G,  Fig.  42,  is  the 
plan,  a  perfect  circle,  of  twelve  feet 
diameter  or  six  feet  radius,  A  D  and  B 
F  two  diameters  or  centre  lines  inter- 
secting in  the  centre.  The  dome  is 
hemispherical  or  half  a  ball,  or  sphere, 
therefore  the  elevation  H  J  I.  is  struck 
from  a  six  foot  radius.  A  pair  of  tram- 
mel points  and  rod  may  be  used  in  strik- 
ing out  these  curves,  but,  should  these 


be  lacking,  a  £  by  $  inch  strip  and  a 
couple  of  brad  awls  will  do  the  job  very 
handily. 

H,  I,  are  the  plates  made  of  thick- 
nesses of  stuff,  and  I  J  one  pattern 
rafter.  J  is  the  top  cut  and  I  the  bottom 
cut.  They  are,  of  course,  similar.  The 
rafters  for  this  roof  may  be  gotten  out 
of  H  or  2  inch  stuff,  fastened  at  the 
joint  by  a  cleat  as  shotvn  at  I  J.  There 
will  be  eight  rafters  required  (if  it  is  in- 
tended to  cover  it  vertically)  as  B  X, 
C  X,  D  X,  E  X.  F  X,  G  X,  H  X.  3  X, 
and  these  will  have  horizontal  sweeps 
nailed  in  between  them  denoted 
here  by  1.  2,  3,  4,  5,  in  the  ele- 
vation/ The  exact  position  of  these 
sweeps  is  determined  by  dividing  the 
quarter  circle  H  J  into  six  equal  parts 
and  then  from  the  division  points,  draw- 
ing lines  parallel  to  H  I.  These  will  be 
the  centre  lines  of  the  edges  oi  the 
sweeps. 

Similarly  they  are  shown  on  the  plan 
below  as  1,  2.  3,  4,  5.  to  X  F.  which  is 
as  they  will  look  from  above.  Their 
exact  length  for  each  course  from  1  to  5 
will  be  found  by  measuring  the  sweeps 
from  A  X  to  G  X.  deducting  half  the 
thickness  of  the  rafters  on  each  end. 
Patterns  should  be  made  for  each 
course  as  it  will  be  seen  that  each  is 
struck  from  a  different  radius,  shorten- 
ing as  they  ascend  to  the  top.  1  in  the 
plan  corresponding  to  1  in  the  elevation 
and  so  on  up.  It  will,  therefore,  be 
clearly  understood  how  to  frame  such  a 
roof  as  this  when  boarded  or  covered 
vertically. 

To  find  the  exact  shape  and  size  of  the 
covering  boards,  take  any  one  of  the  six 
divisions  and  set  it  off  on  each  side  of  G, 
the  point  where  X  G,  cuts  the  quarter 
circle  A  F,  at  G;  produce  X  G,  indefi- 
nitely. Now,  with  the  dividers  set  off 


ROOF  FRAMING  MADE  EASY. 


on  G  S,  the  six  distances,  H  I,  1  2,  2  3, 
3  4,  4  5,  5  J;  and  draw  lines  from  these 
points  square  to  G  S.  Next  again  with 
the  dividers  make  these  squared  lines 
each  equal  in  length  those  dotted  lines 
passing  through  G  X,  from  T  to  U,  and 
draw  the  curves  as  shown,  which  will 
give  the  exact  length  and  curvature  of 
the  boards  to  be  bent  round  I  J.  There 


will  be  12  of  these  for  each  quarter  cir- 
cle on  plan  or  24  for  the  whole  roof.  If 
this  be  laid  out  on  a  cardboard  sheet  it 
will  be  found  to  fit  exactly. 

To  cover  this  roof  horizontally,  all  the 
rafters,  24  in  number,  must  be  set  ver- 
tically or  plumb,  as  B  X.  1  X,  2  X,  etc. , 
to  A  X,  and  it  would  be  best  to  have  a 
finial  or  block  at  the  top  to  receive  the 
top  ends  of  the  rafters.  In  order  to  find 
the  shape  of  the  level  covering  boards, 


Fia.  42. 


34 


ROOF  FRAMING  MADE  EASY. 


FIG.  43. 


divide  the  curve  Fig.  43,  into  6  equal 
parts  and  draw  line  from  division  points 
parallel  to  plate.  Join  A  1.  1  2,  2  3.  3  4, 
4  5,  5  6,  and  produce  these  joining  lines 
till  they  cut  the  centre  line  produced 
indefinitely.  The  points  where  these 
produced  lines  intersect  the  centre  line 
will  be  the  centres  for  the  curves  of  the 
covering  boards  as  represented  in  the 
engraving. 

CHAPTER  XVII. 

To     FRAME     A     CIRCULAR     ELLIPTIC 
DOME. 

READERS  will  observe  that  I  have 
here  treated  a  roof  with  which 
most  mechanics  are  unfamiliar, 
and  it  is  a  pleasure  for  me  to  de- 
scribe it  for  this  reason.     A  C  D  B,  Fig. 
44,  is  the  plan  or  outside  line  of  the 
plates  which  measure  12'  0"  x  20'  0",  or 
the  roof  will  be  20  feet  long  and  12  feet 
wide.     Across  IK  R  its  section  will  be 
a  semi-circle,  or  A  E  B  and  across  F  K 
S  its  section  will  be  a  semi-ellipse  (not 
an  oval,  as  this    figure    is    often   mis- 


called). As  there  may  probably  be  some 
readers  who  are  not  acquainted  with  the 
proper  methods  of  striking  a  semi- 
ellipse,  as  H  M  L  H  C  really  is  we  will 
proceed  to  illustrate  and  describe  the 
best  in  use. 

In  referring  to  the  engraving,  Fig.  45, 
we  will  suppose  A  B  to  be  20  feet  long 
and  C  D  6  feet  equal  to  the  E  F  011  Fig. 
44.  Now  to  find  exact  curve  of  the 
ellipse  draw  the  line  R  C  F  parallel  to  A 
D  B.  and  draw  F  E  and  B  F.  Now 
divide  the  sides  E  C  and  C  F  each  into 
five  equal  parts  as  1 2  3  4  and  E  and  join 
these  dividing  points  with  the  angle  A, 
as4A,  3A,  2A,  1A.  and  CA.  Similar 
lines  are  drawn  on  the  other  side  to  B. 
After  this  is  done,  divide  the  sides  AE 
and  BF  each  into  five  equal  parts  and 
join  the  dividing  points  with  C,  as  AC, 
1C,  2C,  etc  ;  do  likewise  on  the  side  BF. 
Next  proceed  to  trace  the  elliptic  curve 
through  the  points  where  the  joining 
lines  intersect  each  other,  as  shown  in 
the  diagram,  Fig.  45.  This  is  the  exact 
method  of  drawing  an  ellipse,  but  as  it 
is  not  always  applicable  in  the  case  of 
large  spans  like  on  this  roof  I  would 


ROOF  FRAMING  MADE  EASY. 


35 


FIG.  44. 

recommend  mechanics  to  use  the  tram- 
mel method  illustrated  in  Fig.  46.  The 
trammel  is  made  of  two  pieces  of 
grooved  stuff  halved  together  in  the  way 
denoted  by  the  heavy  black  lines  in  the 
engraving.  In  the  groove  two  little 
runners  slide,  and  to  them  is  loosely  at- 
tached a  rod  as  ACB  in  Fig.  46.  'The 
distance  from  A  to  B,  Fig.  46,  is  equal 
to  half  the  long  diameter  of  the  ellipse, 
or  from  A  to  I  or  I  to  C.  on  Fig.  44,  and 
the  distance  from  C  to  B  is  the  same  as 
the  height  on  from  I  to  H,  on  Fig  44. 
At  B  the  pencil  is  placed,  and  being 
moved  round,  as  it  were,  the  slides  run 
in  the  grooves  and  the  pencil  follows 
and  outlines  the  desired  elliptic  curve. 
By  means  of  the  trammel  the  full  ellipse 
may  be  outlined  as  shown  by  the  dotted 


line  on  the  under  side.  Fig.  47 
gives  another,  but  less  accurate, 
method  of  obtaining  this  curve. 
AB  is  the  length,  CD  the  height. 
Take  a  rod  and  set  off  the  length 
AC  from  D  on  the  line  AB .  This 
will  give  the  two  face  or  points  E 
and  F.  Drive  nails  or  pins  into 
these  points  and  to  them  attach  a 
btring  which  will  reach  exactly  to 
D.  Now  place  a  pencil  inside  the 
string  at  D  and  trace  the  curve  as 
shown.  This  is  a  very  simple  way 
to  gain  an  elliptic  curve,  but  is 
not  a  very  true  one  on  account  of 
the  stretching  of  the  string.  It  is. 
however,  good  enough  for  small 
curves.  Where  the  trammel  is 
not  available  ellipses  cannot  jpos- 
sibly  be  accurately  described  with 
compasses . 

Having     described     the     best 
methods  of   striking  out  elliptic 
curves  we  will  refer  back  to  Fig. 
44.     We  find  the  cross  and  longi- 
tudinal or  length  sections  to  be  a 
circle  and  an  ellipse.      Now  to 
frame  the  dome  join  BC  and  AD 
on  the  plane,  and  on  each  side  of 
the    centre  line  set  off  half  the 
thickness  of  the  hips — inch,  inch 
and  a-half  or  two  inches,  accord- 
ing to  the  thickness .     Next  draw 
the  seats  of  the  jack  rafters,  nine  on 
each  side,  and  five  on  each  end,  reaching 
from  the  plates  to  the  hips. 

To  find  the  necessary  outline  of  the 
hip  rafters,  which,  being  the  intersection 
of  an  ellipse  and  a  semi-circle  will  be 
also  of  elliptic  form,  from  the  centre  K, 
raise  up  the  height  K  J,  equal  to  H  I, 
and  proceed  to  strike  the  curve  by  any 
of  the  methods  described;  A  J  D,  J  D, 
will  be  the  outline  of  the  top  edge  of  the 
hip  rafter.  For  the  jacks  draw  lines 
from  the  hips  on  the  seat  lines  cutting 
the  quadrant  E  B,  in  N.  O  P  Q,  which 
will  give  the  exact  lengths  of  the  semi- 
circular jacks  N,  on  plan;  O,  on  section, 
to  O,  on  plan,  and  so  on  up  to  R,  which 


FIG.  45. 


FIG.  46. 


36 


ROOF  FRAMING  MADE  EASY. 
33 


AT 


FIG.  50. 


Fia.  51 


ROOF  FRAMING  MADE  EASY. 


37 


rafter  will  be  a  quadrant  as  E  B.  In  the 
same  way  the  two  elliptic  jack  rafters 
on  each  side  of  K  F,  as  M,  and  L,  are 
found  by  the  dotted  lines.  The  plumb 
cuts  will  be,  as  usual,  plumb,  and  the 
side  bevels  will  be  those  seen  on  the  plan. 
To  those  who  have  the  time  and 
patience,  I  would  recommend  that  they 
make  scale  models  of  these  roofs  from 


engraving.  In  striking  this  plan,  any 
of  the  methods  which  I  described  in  the 
last  chapter,  or  by  the  simple  and 
accurate  method  which  I  here  illus- 
trate at  Fig.  48.  It  consists  of 
one  horizontal  straight  edge  A  B, 
tacked  on  the  floor  on  the  line  of 
the  major  axis  or  long  diameter  of  the 
ellipse,  and  a  second  straight  edge  C  E, 


the  descriptions  given  in  previous  chap- 
ters and  in  this.  Nothing  verifies  and 
proves  the  value  of  a  system  of  lines 
like  an  accurate  model  or  true  repre- 
sentation of  the  actually  constructed 
roof  on  a  small  scale,  and  it  is  my  great 
desire  to  publish  nothing  which  is  not 
both  accurate  and  necessary. 


CHAPTER  XVIII. 

To  FRAME  AN  ELLIPTIC  DOME  WITH  AS 
ELLIPTIC  PLAN. 

AT  Fig.  49,  the  plan  of  the  elliptic 
roof.  letABCDEFGHIJK 
L  M  N  O  and  P  be  its  shape  on 
the  outside  line  of  the  elliptic 
plate,  cut  in  sweeps  as  shown  in  the 


:FiG.  48. 

set  on  the  minor  axis  or  short  diameter 
below  it .  These  are  represented  in  the 
engraving.  A  trammel  rod  or  tracer  is 
made  with  the  distance  from  the  pencil 
to  the  farthest  nail  against  the  short 
straight  equal  to  A  C  or  half  the  long 
diameter,  and  the  distance  from  the 
pencil  to  the  nearest  nail  sliding  against 
the  long  straight  edge,  equal  to  C  D  or 
half  the  short  diameter.  The  elliptic 
curves  may  by  this  method  be  accurately 
struck  to  the  size  desired. 


N 


38 


ROOF  FRAMING  MADE  EASY. 


In  this  dome  roof  I  have  inserted  a 
boss  in  the  centre  to  receive  the  top  cuts 
of  the  elliptic  rafters,  all  of  which  rad- 
iate from  the  centre  to  the  outside  edge 
of  the  plate  terminating  at  A  B  C  D,  etc. 
The  rafters  which  will  stand  over  the 
plan,  Fig,  49,  on  M  E  will  be  A  D  and  D 
B  on  Fig.  50,  which  is  the  projection  or 
view  of  elliptic  rafters  nailed  in  position. 

Each  set  of  two  rafters,  as  AI.  BJ, 
CK,  DL,  Fig.  49,  etc.,  must  be  struck 
out  separately  with  the  major  axis  or 
long  diameter  of  each,  being  the  plan 
length  as  AI,  BJ,  etc.,  with  the  minor 
as  CD,  Fig.  50;  great  care  and  accuracy 
is  necessary  in  striking  out  each  set  so  as 
to  have  them,  the  curves,  absolutely  cor- 
rect and  appear  as  at  Fig.  50  when  raised . 

In  order  to  determine  the  shape  of  the 
covering  boards  or  roof  covering  proceed 
to  Fig.  51  and  draw  the  long  diameter 
LMK,  also  the  short  diameter  MA,  and 


FIG.    52.— PLAN    OF   PLATE,  RAFTERS 
AND  SWEEP. 

strike  the  elliptic  elevation  of  the  roof 
LAK.  Divide  the  quarter  ellipse  into 
ten  equal  divisions  as  denoted  by  A  B  C 
D  E  F  G  H  I  J  K  and  let  fall  lines 
square  to  M  K  as  A  M,  Bl,  C2,  etc.,  and 
produce  these  across  the  plan  below,  to 
represent  1 0  boards  bent  across  the 
rafters.  To  find  the  exact  shape  of  these 
covering  boards  join  the  division  points 
on  the  curve  A  K,  and  produce  each  till 
it  cuts  the  line  M  K  produced.  The 
points  where  these  lines  intersect  will 
be  the  centres  from  which  the  curved 
boards,  which  are  necessary  to  bend 
across  the  rafters,  may  be  struck  in  the 
way  represented  in  the  engraving,  Fig. 
51.  For  the  purpose  of  fully  proving 
the  correctness  of  the  above  methods  I 
would  urge  upon  mechanics  to  make  a 
scale  model  as  before  in  cardboard  of 
this  roof,  thus  proving  the  exactness  of 
the  methods  set  forth  in  the  foregoing. 


J  L,  K 

FIG.     53. — MOLDED    RAFTERS.    PLATE 

AND   SWEEPS. 

CHAPTER  XIX. 

FRAMING  A  CIRCULAR   MOLDED   ROOF 

TOWER. 

T   T  AVING  before  described  the  proper 
LX|      methods  to  be  followed  in  fram- 
1    1     ing  a  straight  sided    or  conical 
roof  with  a  circular  base  of  plan, 
in  this  chapter  I  will  give  readers  the  in- 
formation necessary  to  know  in  laying 
out  and  framing  a  roof  with  a  molded 
form  of  rafter.    As  there  are  many  of 
these  constructed  now-a-days  it  will  no 
doubt  be  welcome  to  studious  mechanics. 
By  referring  to  Fig.  52  it  will  be  seen 
that  the  plate  or  plan  is  a  complete  cir- 
cle, asABCDEFGH,  made  up  in 
two  thicknesses  of  sweeps  cut  out  as  1. 


FIG.  54.— How  TO  LAY  OUT  CURVE  OF 
RAFTERS. 


ROOF  FRAMING  MADE  EASY. 


39 


have  shown  by  the  joint  lines.  The 
molded  rafters  (of  a  bell  shape)  are,  as 
seen  on  plan,  eight  in  number  and  must 
be  made  exactly  to  the  curvature  repre- 

f 
It 


FIG.  55. — METHODS  FOR  OBTAINING  SHAPE  OF 
COVERING  BOARDS. 


sented  on  the  projected  framing  of  the 
roof  or  rafters,  etc.,  raised  as  seen  at 
Fig  53. 

In  order  to  obtain  the  exact  flexure 
or  curves  the  writer  has  followed  the 
following  method  with  much  success 
and  shaped  many  molded  rafters  to  the 
design  intended  by  the  architect:  1st, 
make  a  laying-out  floor  out  of  a  number 
of  boards  placed  level  on  planks,  or 
sweep  an  ordinary  floor  clean,  big 
enough  to  lay  the  roof  out  in,  and  draw 
any  base  line  as  A  B  in  Fig.  54;  also 
divide  it  in  the  centre  at  C,  and  draw 
an  exactly  vertical  or  plumb  line  to  it, 
as  C  D,  then  divide  the  height  line  C  D 
into  12  equal  parts  as  1  2  3,  etc.,  and 
draw  through  these  lines  parallel  to  A 
B,  as  1 1,  2  5J,  and  so  on  up  to  11.  Now 
set  off  the  lengths  11,22,  and  so  on  up, 
and  trace  the  bell- shaped  curves  to  the 
desired  flexure .  If  the  architect  furnish 
only  a  ^-scale  drawing  of  the  roof,  the 
scale  drawing  can  be  similarly  lined  off 
and  the  lengths  taken  with  the  scale 
rule,  transferred  and  relaid  on  out  on 
the  floor,  thus  obtaining  the  curve. 

When  the  curve 
is  laid  out  on  a 
drawing-board  the 
pattern  rafter  is 
made  by  placing 
the  planks  on  the 
lines  and  marking 
on  it  the  length 
before  as  described 
and  in  the  manner 
illustrated  in  Fig. 
54,  where  a  rafter 
sawn  out  is  de- 
lineated on  the  left 
hand  side,  as  A  D, 
and  the  thickness 
of  the  6 -inch  boss 
at  D,  which  is  in- 
serted for  the  pur- 
pose of  giving  a 
better  nailing  at 
the  peak,  is  taken 
from  the  top  cut. 
This  boss  is  also 
seen  on  the  plan, 
Fig.  52  at  X,  and 
on  the  projection 
of  set-up  rafters, 
Fig.  53  at  M,  where 
it  is  obviously  nec- 
essary in  order  to 
obtain  a  firm  nail- 
ing for  the  top  ends 
of  the  molded  raft- 
ers. At  Fig.  53  the 
mechanic  will  see 
how  a  series  of 
circular  strips  or 
sweeps  as  they  are 


40 


ROOF  FRAMING  MADE  EASY. 


technically  termed,  are  nailed  in,  rang- 
ing from  the  plate  to  the  peak.  These 
are  essential  when  it  is  intended  to 
board  the  roof  from  bottom  to  top,  for 
the  purpose  of  nailing  the  boards  to 
them. 

They  are  sweeps  or  arcs  of  circles  and 
struck  from  different  radii,  decreasing 
as  they  go  up.  This  will  be  readily  un- 
derstood by  studying  the  plan,  Fig.  52, 
where  the  dotted  lines  represent  the  out- 
side edges  of  the  sweeps  shown  on  Fig. 
53.  As  there  are  8  intervening  spaces 
between  the  rafters,  and  there  are  9  in 
the  height,  there  will  be  72  needed  al- 
together or  8  of  each  kind,  and  they 
may  be  solidly  nailed  in  the  way  indi- 
cated in  the  engraving,  Fig.  53. 

This  form  of  roof  may  be  covered  in 
two  ways,  either  vertically  or  horizon- 
tally. When  covered  vertically,  the 
sweeps  described  above  are  inserted  and 
the  shape  of  the  covering  boards  de- 
termined, in  the  following  manner.  Let 
ABCDEF  GHI  JKLM  NO  Pon 
Fig.  55  be  the  plan  of  the  outside  edge  of 
the  circular  plate,  and  A  X,  C  X,  E  X, 
G  X,  I  X,  K  X,  M  X,  and  O  X  be  the 
rafters,  all  abutting  against  the  boss  X, 
on  plan,  in  the  manner  seen  at  D,  Fig. 
54 ;  also  suppose  the  dotted  lines  on  Fig. 
54  represent  the  outside  edges  of  the 
sweeps.  Now  to  determine  the  shape  of 
one  covering  board,  produce  X  C  to  U 
and  on  the  line  E  U.  taking  U  as  centre, 
proceed  to  strike  the  arcs  a  b,  c  d.  e  f, 
g  h,  i  j,  k  /,  m  n,  o  p,  q  r,  s  t  cutting  U 
C  at  the  points  123456789  10.  Then 
set  off  on  each  side  of  the  line  U  C  on 
each  arc  the  distances  from  X  B  on  the 
p\B,u,taking  the  exact  full  length  of  the 
curve  and  not  on  a  straight  line,  each 
corresponding  as  shown  in  the  engrav- 
ing. For  instance,  s  c  t  must  be  the 
full  length  of  the  curve  BCD,  and  so 
on  with  each  all  the  way  up . 

If  the  roof  is  intended  to  be  boarded 
horizontally  then  more  rafters  must  be 
inserted,  in  order  to  give  a  better  nail- 
ing, and  this  roof  will  then  need  sixteen, 
instead  of  only  eight,  as  before,  see  Fig. 
55.  To  obtain  the  shape  of  the  horizon- 
tal covering  boards,  proceed  to  the  upper 
engraving  and  draw  Q  R  equal  to  M  E 
below,  and  S  T  vertical  to  it.  Also  set 
off  the  bell-shaped  curves  as  shown. 

To  find  the  shape  of  the  first  or  bot- 
tom board,  assume  R  V  to  be  a  straight 
line,  and  produce  it  till  it  cuts  the  verti- 
cal line  S  T  at  W,  then  with  W  as  cen- 
tre and  radii  W  R  and  W  V,  strike  the 
two  arcs  Q  R  Z  and  Q  V  Y .  Finally, 
to  find  the  exact  length  of  this  bottom 
board,  take  any  curved  distance  on  plan, 
as  A  B.  Fig.  55,  and  set  it  off  eight  times 
from  Q  to  Z,  as  indicated  by  the  marks. 


This  will  give  half  way  round,  which 
doubled  will  give  entire  circular  cover- 
ing board  for  the  first  section.  By  con- 
tinuing this  process  up  to  the  top,  all  the 
horizontal  boards  may  be  laid  out. 


CHAPTER  XX. 

To  FRAME  A  GOTHIC  TOWER  ROOF  OF 
FOUR-CENTRE  SECTION. 

1HERE  set  before  readers,  a  form  of 
roof  which  is  fast  becoming  popular 
on  account  of  its  uniform  curves. 

As  the  section  of  the  roof  is  a  com- 
bination of  curves,  we  must  first  pro- 
ceed to  lay  it  out .  On  a  large  floor  or 
platform  draw  the  spring  line  AB,  Fig. 
56.  Divide  this  line  AB  into  4  equal 
parts  as  1,  2,  3  and  4;  also  from  A  and 


FIG.  56. 

B,  draw  AC  and  BD  square  to  AB.  Now 
with  A  as  centre  and  A2  as  radius  strike 
the  curve  2C,  cutting  AC  at  point  C. 
likewise  strike  the  curve  2D  cutting  BD 
at  D.  This  process  locates  the  desired 
centres  for  the  different  curves  of  the 
dome  or  tower  section. 

With  1  as  centre  and  1  A  length  of 
radius,  strike  the  short  curve,  or  arc  A 
E  and  with  3  as  centre  and  same  radius 
strike  B  F.  This  gives  2  arcs,  next  with 
C  as  centre,  and  allowing  the  trammel 
pencil  to  be  just  tangent  to  B  F  at  F, 
describe  the  arc  F  G.  In  a  similar 
manner  describe  the  arc  E  G  on  the  left. 
This  process  carefully  followed  out  will 

five  the  exact  four-centre  gothic  section, 
ut  it  must  not  be  followed  in  every 
plan  where  a  roof  of    this    section  is 
shown,  as  the  position  of  the  centres  may 
not  be  placed  or  divided  off  as  is  shown 


ROOF  FRAMING  MADE  EASY. 


above,  and  a  detail  or  layout  of  the  roof 
may  be  necessary  to  determine  their 
position.  The  foregoing  description, 
however,  will  make  the  work  familiar 
and  easy. 

In  order  to  lay  out  the  rafters  for  this 
roof,  proceed  to  Fig.  57,  and  lay  out  the 
plan  full  size  A  B  C  D,  also  draw  the 
diagonals  A  D  and  B  C.  the  seats  of  the 
hips,  with  the  jacks  abcdefghij, 
against  the  hip  seat  c  X.  On  the  line 
B  D,  divided  in  half  at  E.  raise  up  the 
gothic  section  line,  and  from  this  sec- 
tion make  a  paper  or  wood  pattern  rafter 
to  the  curve  B  12.  in  the  manner  shown 
in  the  engraving.  Divide  B  12,  into 
twelve  equal  parts,  as  1,  2,  3,  4,  etc., 
and  from  each  division  point  draw  a 
line  square  to  the  line  BED,  and  pro- 
duce these  lines  to  the  hip  seat. 

B  12,  will,  of  course,  be  the  common 
rafter  standing  over  E  X.  Each  jack 
will,  because  the  hip  rafter  is  on  a  mitre 
or  angle  of  45  degrees,  be  shorter  as  they 
go  down  from  X  to  C,  and  their  lengths 
will  be  as  K  11,  L  10,  M  9,  N  7,  and  so 
on  down  to  B. 

At  Fig.  58,  readers  will  see  a  compar- 
atively simple  method  which  may  be 
followed  to  obtain  the  top  side  bevel  of 
the  jack  rafters.  A  B.  is  the  common, 
showing  its  upper  edge.  Set  off  rafter 
No.  10  from  A  to  C.  C  D,  being  the  ver- 


FIG.  57. 


FIG.  58. 

tical  or  plum  cut.  Square  across  from 
the  upper  edge  corner,  from  G  to  C,  as 
C  F,  and  from  C  D,  set  off  the  thickness 
of  the  jack  rafter,  2  inches,  or  3  inches, 
or  whatever  it  may  be.  The  bevel  will 
be  as  shown  in  the  engraving. 

B  X.     From  the  points  where  these 
dotted  lines  cut  B  X,  draw  up  square  to 
BX,  lines  of  an  indefinite  length.     Now, 
commencing  from  B,  on  line  B  E,  take 
the  first  division  1,  and  set  off  the 
height  from  the  line  to  1,   on  the 
first  line  on  the  hip  seat,  also  height 
at  2,  3,  4,  5,  and  so  on  up  to  12". 
To  be  explicit,  I  would  say  transfer 
these  heights  from  perpendiculars 
on  B  E,  to  perpendiculars  on  B  X. 
Next  trace  the  curve,  F  B,  through 
the  points  12,  11,  10,  etc.,  and  the 
proper  outline  of  hip  rafter  will  be 
found. 


CHAPTER  XXI. 

To  FRAME  A  TRUSSED   ROOF    OF 

LARGE  SPAN  ON  THE  BALLOON 

PRINCIPLE. 

THAT  carpentry  is  a  progres- 
sive art  is  a  truism  that  the 
observer  will  not  hesitate  to 
admit,  and  a  careful  exami- 
nation of  the  timber  structures  be- 
ing erected  in  the  United   States 
to-day  will  impress  the  examiner 
with  the  fact  that  it  is  also  a  liberal 
art.     This  is,  without  doubt,  one  of 
the    chief  reasons  why  wood  has 
not  been  entirely  driven  out  of  the 
field  by  its  great  competitor,  iron, 
as  it  can    be    readily  and    econo- 
mically employed  where  the  latter 


ROOF  FRAMING  MADE  EASY. 


\ 


\ 


'  '  \  X 

*  '  /  v       X 

V  ___    „      _     .  _/_  \    X 


I  / 

\    I       / 

\     I  ' 

-  I        / 

\i  ,_  _K 

/<r/        - 

/        x/ 

/          /\  " 

/     x  / 


FIG.  59. 


material  would  be  inadaptable.  The 
numerous  and  exceedingly  artistic  dwell- 
ings which  are  erected  in  all  parts  of  the 
country  attest  this,  and  while  designing 
them  the  architects  have  endeavored  to 
devise  new  forms  of  construction  which 
might  enable  them  to  produce  an  effec- 
tive design  and  at  the  same  time  be  a 
cheap  one  to  build.  An  illustration  of 
this  will  be  seen  in  the  sketches  which 
are  here  introduced,  as  they  explain  a 
unique  method  of  balloon  framing  which 
was  adopted  in  a  church,  the  building 
being  a  frame  structure,  and  having  an 
auditorium  measuring  56  feet  square. 
The  architect  wished  to  avoid  inserting 
the  usual  form  of  trusses  and,  after 
careful  study,  he  devised  the  manner  of 
construction  here  shown .  Fig.  59  is  the 
plan  of  the  auditorium,  E  A  D  G  C  I  B 
E  being  the  outside  line.  B  F  A,  A  L 
D,  D  H  C  and  C  J  B  are  the  trusses 
which  the  reader  will  notice  do  not  span 
the  roof  at  right  angles  in  the  way  gen- 
erally followed,  but  are  placed  at  an 
angle  of  45  degrees  across  the  angle  of 
the  corner.  Each  of  these  were  25  feet 
on  base  line  and  were  framed  in  the  way 
represented  in  the  isometrical  projected 
view  (see  frontispiece),  without  any  tie 
beam,  yet  of  a  form  statically  strong 
enough  to  support  the  rafters  and  shing- 
ling placed  upon  it.  They  were  then 


placed  diagonally  across  the  plan  so 
that  their  seats  formed  a  square,  as  it 
were,  within  a  square.  This  the  reader 
will  comprehend  better  by  referring 
again  to  Fig.  59,  where  the  dotted  lines 
A  D,  D  C,  C  B  and  B  A,  are  the  seats  of 
the  trusses,  and  a  close  observation  of 
the  projection  (see  frontispiece),  will  give 
him  a  perfect  idea  of  how  they  were 
positioned.  The  hip  rafters  E  F,  K,  D,  G 
H  and  I  J,  rested  against  the  trusses 
which  supported  on  their  peaks  the  up 
per  wall  plate  or  purlin  on  which  the 
ventilator  was  raised,  and  against  which 
the  jack  rafters  from  the  trusses  rested. 
A  peculiar  feature  of  the  construction, 
which  the  reader  will  notice,  is  that  the 
principal  rafter  of  the  trusses  in  each 
plane  of  three,  as  D  I  and  D  H.  in  the 
plane  G  H  L  K.  was  partly  a  hip  and 
partly  a  valley  rafter  at  the  same  time, 
because  the  jacks  were  cut  from  the 
plates  below  to  them  and  from  them  to 
the  purlin  above;  but  the  sides  still 
formed  separate  planes  and,  when  cov- 
ered, showed  a  straight  surface,  as  G  H 
L  K,  Fig.  59.  Taking  the  whole  con- 
struction as  a  piece  of  statical  and 
economical  design,  it  savors  more  of  en- 
gineering than  architecture,  but  as  an 
uncommon  piece  of  roof  framing  it  is 
a  most  ingenious  method  of  solving  an 
old  problem  in  a  new  way. 


ROOF  FRAMING  MADE  EASY. 


FIG.  61.— ROOF  TIMBERS  WHEN  RAISED. 


CHAPTER  XXII. 

To  FRAME  A  ROOF  OF  UNEQUAL  HEIGHTS 
OF  PITCHES  AND  PLATES. 

HAVING  described  in  previous  chap- 
ters  roofs  springing  from   wall 
plates  on  the  same  level,  I  will 
show  in  this  the  proper  method 
to  be  followed    in  framing  two  roofs 
where  the  plates  are  at  different  heights 
and    the    roofs    at     different     pitches. 
These  roofs  to  those  unused  to  them 
appear  very  difficult  to  frame,  but  are 
really  not  so. 

Fig.  61  will  give  readers  a  full  con- 
ception of  the  timbers  forming  the  two 
roofs  as  they  will  appear  when  "raised" 
or  set  up  in  their  permanent  position. 
It  will  be  noticed  that  the  wall-plate  of 
the  projection  or  bay  is  about  four  feet 
higher  than  the  plate  on  the  main  wall 
of  the  house,  also  that  the  rafters  are 
cut  on  different  pitches. 

If  the  reader  cannot  clearly  under 
stand  this  I  would  refer  him  to  Fig.  62. 
which  is  a  sectional  view  of  the  roof 
when  raised  through  the  line  A  B,  on 
Fig.  63,  the  plan  of  roofs.  Here  the 
different  levels  of  the  plates  will  be  seen 


and  another  view  of  the  rafters  and  stud 
wall  of  the  projection.  As  the  timbers 
are  all  marked  very  little  description  is 
necessary. 

Concerning  the  methods  to  be  fol- 
lowed in  finding  the  lines  for  this  form, 
it  is  as  f ollows :  C  D  E  F.  Fig.  63,  is  the 
plan  of  the  extension  plates,  I  and  J 
being  the  plates  of  the  main  house  wall. 


FIG.  62. — SECTION  ON  LINE  A  B. 


ROOF  FRAMING  MADE  EASY 


G  C  and  G  F  are  the  seats  or  plans  of  the 
valleys  determined  by  the  intersection 
of  the  two  peaked  roofs.  To  find  the 
exact  length  of  these  valleys  raise  up 
square  the  pitch  G  K.  Set  off  the  height 
G  K  equal  to  A  B  Fig.  62,  and  join  K  F, 
which  line  is  the  exact  length  of  the 
valley  rafter  as  seen  at  Figs.  61  and  62, 
also  the  length  of  G  C. 

Next,  to  find  the  lengths  of  the  jack 
rafters  on  each  side  of  the  valleys  set  a 


f 


JDL 


FIG.  63.— PLAN  OF  ROOFS. 

pair  of  compasses  to  the  line  K  F,  and 
with  F  as  centre  cut  the  line  H  G  L  at  L 
and  join  L  F.  Now  if  the  jacks  from 
the  ridge  line  H  G  be  produced  to  the 
line  L  F  their  exact  length  will  be  given 
with  the  side  or  top  edge  bevel.  To 
obtain  the  length  of  the  jack  rafters  on 
the  main  roof,  the  feet  of  which  nail 
against  the  valleys,  draw  R  M  parallel 
to  L  F  and  the  lengths  of  these  jacks 
will  be  thus  found. 


CHAPTER  XXIII. 

To  FRAME  A  HIP  AND  VALLEY  ROOF 
OF  UNEQUAL  PITCH. 

FIGURE  64  is  the  projection  of  the 
roofs  completed,  and  it  will  be 
noticed  that  they  are  of  different 
pitches  and  widths.     A  B  C  D  E  F 
G  M  H  K  IJ,  Fig.  65,  is  the  plan  of  the 
building.     A  B  is  a  gable  end,  and  A  N 
is  the  length  of  the  common  rafter ;  also 
D  E  is  a  gable  end.     D  O  being  the 
length  of  the  common  rafter  each  has  a 
ridge  L  N  X  and  P  O  Y.     The  main  roof 


is  hipped,  having  four  principal  hip 
rafters  with  jacks.  The  intersection  of 
each  of  the  L's  on  the  building  with  or 
rather  in  the  main  roof  gives  three  val- 
iey  rafters  and  creates  the  framing 
p  oblem  which  is  to  be  worked  out. 

Proceed  to  lay  out  the  plan  of  the 
plates,  hips,  valleys  and  ridges  as  shown 
on  Fig.  66,  and  join  I  G  and  H  Q  giving 
the  peak  R ;  also  draw  the  dotted  lines 
K  R  F  and  M  R  X  in  Fig.  65.  To  ob- 
tain the  length  of  the  main  hip  rafters 
square  up  from  R  and  set  off  on  the 
square  line  the  pitch  height  R  C  equal 
to  E  T.  Join  H  S,  which  will  be  the 
exact  length  of  the  hip  rafter,  with  the 
bevel  S  for  the  top  cut  and  the  bevel  H 
for  the  bottom  cut. 


FIG.  64.— ELEVATION  OF  ROOF. 

To  find  the  lengths  of  the  jacks  set  a 
pair  of  compasses  or  a  rod  at  Hand  with 
H  S  as  radius  sweep  the  arc  S  V .  Join 
V  where  the  arc  cuts  the  line  R  F  and 
H,  also  draw  the  jack  rafters  square  to 
the  plate  K  H  until  they  reach  the  line 
V  H,  and  this  line  will  determine  their 
length  and  the  bevel  U  will  be  the  cut 
across  the  top  of  each  against  the  hip, 
that  at  I  being  the  plumb  cut.  Reverse 
cuts  are  made  to  go  against  the  hip  I  R 
and  G  R,  from  the  plates  K  I  and  G  F. 

To  find  the  lengths  of  the  jacks  placed 
on  the  plate  G  M  H.  proceed  to  raise  up 
from  R  square  to  G  R,  the  pitch  R  Z ; 
join  Z  G  and  with  G  as  centre  and  rad- 
ius G  Z  sweep  the  arc  Z  X,  cutting  M  R 
N  L  in  X;  join  X  G.  Set  off  the  jack 
rafters  in  the  manner  shown,  reaching 
from  the  plate  G  M  H  to  the  line  G  X 
and  their  lengths  will  be  thus  found. 
The  bevel  W  will  be  the  cut  across  the 
top  edges  of  jacks  in  getting  the  cut  to  fit 
against  the  hip.  It  will  also  be  the  bevel 
reversed  on  the  opposite  to  fit  against 
the  hips  standing  over  Q  R  and  R  I. 

In  framing  the  valleys  to  stand  over 
the  seats  X  C  and  X  J,  first  find  out 
where  the  ridge  will  penetrate  the  main 
roof.  This  may  be  simply  done  by  set- 
ting off  on  the  line  E  T,  the  half  pitch 
height  L  N  and  drawing  out  square  as 
1,  2.  The  point  2  will  be  the  point 
where  the  ridge  L  N  will  enter  the  main 
roof.  This  must  be  transferred  over  to 
cut  the  ridge  X ;  and  J  X,  C  X  will  be 
the  seats  of, the  valleys. 


ROOF  FRAMING  MADE  EASY. 


45 


FIG.  65.— LAYOUT  OF  RAFTERS 


To  find  the  valley  rafters,  square  up. 
from  X.  which  will  be  the  line  X  5,  on 
it  set  off  the;  pitch  N  L,  and  join  J  5 
which  will  be  the  exact  length  of  the 
valley  rafter  with  the  top  and  bottom 
bevels  as  indicated  on  the  diagram.  It 
will  be  here  seen  that  I  have  prolonged 
one  valley  from  X  till  it  cuts  the  centre 
line  of  the  main  roof  and  at  the  point 
where  it  cuts  raised  up  the  whole  pitch 
of  T  E,  as  6  A.  This  is  done  for  the 
purpose  of  determining  the  lengths  of 
the  jack  rafters,  and  is  necessary  to  find 
the  angle.  C  6  F  is  the  angle.  To  find 
the  short  jacks  reaching  from  the  hip 
Q  R  to  the  valley  C  X,  join  C  F  and 
divide  it  into  two  equal  parts  as  6  7. 
Now  with  C  as  centre  and  C  4  as  radius, 
sweep  the  arc  4  8,  cutting  7  6,  produced 
at  8  and  join  C  8 ;  next  draw  the  jack 
rafters  from  R  Q  to  the  dotted  line  C  8, 
which  will  be  their  lengths  and  the  bot- 
tom cuts  across  the  top  edge  of  each 
jack,  nailing  against  the  valley  rafter  6 
C,  will  bethebe-e!9. 

The  jacks  from  the  ridge  L  N  X  to  the 
valley  J  X.  are  found  similarly  by  set- 
ting the  compasses  to  radius  J  5  and 
sweeping  the  arc  cutting  the  line  X  R; 
then  by  joining  this  point  with  J  by  the 
dotted'line  seen  to  the  left  of  the  valley, 
the  jacks  may  be  drawn  as  before. 


For  the  valley  F  Y  raise  up  square 
trom  Y  the  pitch  Y  Y  equal  to  P  O,  and 
join  Y  F  for  the  length  of  valley.  The 
jacks  are  found  by  the  process  described 
before  and  the  bevels  are  clearly  seen . 
Each  hip  and  valley  rafter  should  be 
gotten  out  separately  to  avoid  con- 
fusion, and  the  diagram  closely  studied 
as  the  system  is  simple  and  easily 
understood. 


FIG.  66.— FLAN  OF  ROOF 


46  ROOF  FRAMING  MADE  EASY. 

CHAPTER  XXIV. 


To  FRAME  A  ROOF  OF  UNEQUAL  LENGTHS 
OF  RAFTERS. 

LET  A  B  C  D  in  Fig.  67  be  the  square 
plate  or  lower  plate,  which  has 
short,  or  curb  rafters  supporting 
a  circular  plate,   E  F  G  H,   on 
which  rests  a  drum,  or  short  cylindrical 
tower  as  E  C  D  F,  Fig.  69,  topped  by  a 
roof  with  curved  rafters.     By  referring 
to  the  plan.  Fig.  67, .it  will  be  seen  that 
the  seats  of  the  rafters  will  be  of  differ  - 


PLAN  OF  PLATES  AND  RAFTERS. 


eiit  lengthening  from  the  centre,  or 
number  6,  to  the  corner  or  hip  rafter  I, 
and  that  this  occurs  on  all  four  sides  of 
the  square  plate.  As  the  seats  are  of 
different  lengths  the  rafters  will  also  be 
of  different  lengths,  though  they  have 
the  same  rise  or  pitch,  as  X  Y  in  Fig.  68. 
In  this  figure  the  different  lengths  of 
rafters  will  be  distinctly  seen  decreasing 
in  size  from  the  hip  or  angle  to  the 
centre  of  the  plate,  this  occurring  on 
each  side,  which  will  necessitate  8  sets 
of  five  rafters,  cut  with  right  and  left 
hand  bevels  on  the  plate,  also  one  set  of 


FIG.  69.— PROJECTION  OF  ROOF  AND 
DRUM. 

4  with  square  cut  on  plate,  as  number  6. 
Each  succeeding  rafter  will  have  differ- 
ent top  and  bottom  bevels,  and  require 
great  care  in  laying  out.  so  as  to  cut  the 
timbers  without  waste,  so  that  it  would 
be  wisest  to  lay  out  and  cut  them  in  sets, 
one  for  each  side.  The  top  and  bottom 
cuts  as  represented  in  Fig.  69,  are  also 
notched  to  fit  over  the  plates  and  thus 
prevent  their  slipping;  this  will  also 
demand  care  in  laying  out,  because  each 
notch  will  have  a  different  bevel.  The 
got  hie  roof  on  the  drum  may  be  struck 
out  to  the  curve  shown  and  rafters  cut 
out.  As  all  the  rafters  are  the  same 
length,  they  can  be  sawn  from  one  pat- 
tern, and  set  up  in  the  manner  which  I 
have  already  described. 


FIG.  68. — DIFFERENT  LENGTHS  OF 
RAFTERS. 


CHAPTER  XXV. 

To  FRAME  A  ROOF  WITH  PITCHED 
RIDGES. 

THE  following  roof   of  an  unusual 
kind   will  be  found  of  value  to 
those  carpenters  who  live  in  the 
country  or   whose   duty  it  is  to 
construct  barns,  or  other  special  build- 
ings,  where  great  room   is  required  in 
the  roof  or  attic. 

The  engraving.  Fig.  70,  is  an  isometric 
view  of  the  roof,  and  as  will  be  seen  it 
consists  of  a  roof  of  four  gables  on  a 
square  plan,  with  four  valleys  and  four 
ridges  which  rise  on  a  pitch  from  the 
peaks  of  the  gables  and  terminate  at  the 
peaks  of  the  valleys,  giving  the  effect  as 
shown.  The  rafters  of  the  gables  are 
half  or  mitre  pitch,  and  twelve  and 
twelve  011  the  steel  square.  The  peak  of 
the  valleys  represented  in  Fig.  71  is  4 


ROOF  FRAMING  MADE  EASY. 


47 


/    O 


Fi<;.  7*2— LAYOUT  OF  ROOF. 


48 


ROOF  FRAMING  MADE  EASY. 


feet  higher  than  the  gable  peaks  so  that 
the  ridges  rise  on  pitch  in  the  manner 
shown  in  the  cross  section  Fig.  71,  thus 
forming  a  very  peculiar  and  unusual 
form  of  roof. 

In  order  to  frame  this  roof  in  the  sim- 
plest manner  proceed  to  Fig.  72,  and  let 
A  E,  B,  H,  D  C,  be  the  plan  of  the  roof 
A  F,  B  F.  D  F  and  C  F,  being  the  seats 
of  the  valleys.  E  F,  H  F,  G  F,  and  I  F, 
being  the  seats  or  plans  of  the  hips.  To 
find  length  of  valley  from  F  square  up 
as  F,  A  J,  equal  in  height  to  at  C  Fig.  71, 
and  join  J  C,  Fig.  72  for  the  lengths  and 
bevels  of  the  four  valley  rafters.  Now 
for  the  eighteen  jack  rafters  the  author 
has  found  it  most  convenient  to  develop 
the  roof  in  order  to  prove  the  accuracy 


FIG.  70. — GENERAL  APPI  ARANCE  OF 
ROOF. 

of  the  layout ;  therefore  on  C  G  D,  erect 
one  gable  to  stand  over  C  G  D,  as  C  K  D. 
From  D,  make  D  M,  equal  in  length  to 
F  J,  and  K  M,  equal  in  length  to  the 
ridge  E.,  C,  or  C  F,  Fig.  71.  Divide  off 
on  K  M,  Fig.  3,  the  jack  rafters  as  on  K 
M,  Fig.  71,  and  draw  them  parallel  to 
K  D,  in  the  way  illustrated  at  Fig.  72, 
as  N  O,  P  Q  R  S,  T  U,  V  W,  and  X  Y. 
The  bevels  at  O,  and  N,  Fig.  72,  will  be 
the  side  bevels  against  the  ridges  and 
valleys,  being  reversed  for 
different  right  and  left 
sides,  the  down  or  verti- 
cal cut  of  the  bottom  ends 
of  the  jacks  nailed  against 
the  valley  sides  will  be  as 
the  pitch  of  the  valleys 
and  the  top  cuts  as  that  of 
the  gables  or  mitre  cut. 
Carpenters  should  cut  this 
diagram  out,  as  it  is  print- 
ed, to  prove  the  accuracy 


FIG.  71. — VALLEYS,  RAFTERS  AND 
RIDGES  . 

of  the  methods,  or  first  paste  the  en- 
graving on  cardboard  and  then  cut 
out  as  follows: — Cut  out  the  whole 
plan,  A  E  B  H  D,  M  K  L  C,  and  A; 
then  make  a  slight  cut  with  a  pocket- 
knife  or  chisel  from  C,  to  K,  and  from 
K,  to  D,  also  across  C  G  D.  Fold  over 
the  development  until  K,  is  over  G  D 
M,  is  over  D  F  C  L  over  C  F,  and  L, 
and  M,  joined  together  are  over  F,  with 
the  ridge  L  K,  over  G  F. 


CHAPTER  XXVI. 


To  FRAME  A  ROUND-HOUSE  ROOF. 

ASSUME  the  roof  to  be  semi  circular 
in  plan  as  represented  in  Fig.  74, 
and  to  have  a  pitched  roof  with 
a  ridge,  the  pitch  being  half,  or 
12  and  12  on  the  steel  square,  as  seen  at 
D,  G,  F,  Fig.  74,  where  the  lengths  of 
the  rafters  and  bevels  are  delineated. 
A,  B,  C  and  D,  E,  F,  are  the  gables  on 
the  plan  Fig.  74  seen  on  the  elevation 
Fig.  73,  with  windows  and  doors  in 
same.  In  order  to  find  the  length  of  the 
common  rafter  simply  raise  up  from  E, 
Fig.  74,  the  pitch  or  rise  E,  G  and  join 
D,  G.  As  the  outer  plate  line  A,  X,  F, 
is  much  longer  than  the  inner  plate  line 
C,  Z,  D,  more  rafters  will  be  required  so 
as  to  form  a  sufficient  support  for  the 
roof  boards  and  covering.  For  this  rea- 
son an  extra  rafter  from  the  plate  line 
A,  X,  F,  to  the  ridge  B,  K,  I,  E,  must 


FIG.  73. 


ROOF  FRAMING  MADE  EASY. 


be  inserted  bet  ween  each  abutting  rafter 
so  as  to  equalize  the  spacing  and  obtain 
a  stable  roof. 

The  proper  way  to  find  the  shape  of 
the  roof  boards  is  seen  at  the  bottom 
side  of  Fig.  74.  Divide  D,  H,  into  10 
equal  parts,  or  more  if  desired,  then  with 
O.  as  centre  and  O.  l,as  radius,  describe 
a  curve,  similarly  describe  from  D. 
2,  :'..  4  .I.  I).  7.  8.  9  and  10.  which  will 
of  course  bring  the  boards  up  to  the 


FIG.    T4, 

ridge  line.  Now  take  the  distance  from 
E  to  I  and  set  it  off  from  H  to  P,  the 
centre  of  the  rafter  at  I.  and  this  will 
give  the  lengths  of  boards  for  one  sec- 
tion. A  like  method  can  be  followed 
tor  covering  the  outride  slope  of  the 
roof.  This  roof  is  of  a  very  rare  kind 
and  is  only  found  on  railroads  where 
locomotives  are  stored  or  on  large  estates 
for  barns  or  outhouses. 


CHAPTER  XXVII. 


FRAMING  A  CANTILEVER  ROOF. 

T  N  answer  to  a  letter  requesting  me  to 

illustrate  and  describe  a  cantilever 

1     roof.  I  submit  for  the  benefit  of  all 

students  of  carpentry  the  following 

design   for  a  roof  of  this  description, 

which   will  be  adaptable  either  for  a 

large  shed  or  station. 

The  engraving,  Fig  75,  shows  a 
a  transverse  or  cross  section  of  the  shed, 
which  may  beany  length  desiied,  the 
width  (covered)  shown  is  48'  0".  at  a 
sca'e  of  i  inch  =  1  foot.  If  the  width 


be  reduced  half,  timbers  half  the  width 
and  thickness  given  here  will  be  sum' 
cient  The  height  to  under  side  of 
straining  beam  is  13'  0",  to  ridge  2ti?  6". 
The  construction  of  this  building  is  very 
simple  and  is  fully  illustrated  by  the 
drawing.  It  consists  of  a  series  of  con- 
crete footings  about  3  feet  or  4  feet 
square,  placed  on  sand  or  hard  clay  24' 
0"  apart,  measuring  from  centre  to  cen- 
tre across;  and  10' 0"  apart,  measuring 
from  centre  to  centre, 
longitudinally  or  length- 
ways. On  top  of  these 
footings  is  set  a  good  blue 
or  gianite  stone  mortised 
out  to  receive  the  bottom 
ends  of  the  posts  or  up- 
rights. These  del  ai  Is  con  - 
stitute  the  foundation. 

The  frame  superstruc- 
ture primarily  consists  of 
the  series  of  10"xlO  '  yel- 
low   pine    square    posts, 
which  are  tenoned  at  top 
and  bottom  ends,  at  the 
bottom  to  fit  into  the  hot 
torn  stone  and  at  the  top 
to  receive  the  10"  x  10" 
stringer  beam  or  plate  A . 
This    longitudinal    plate 
or  stringer  is  mortised  to 
receive  the  top  ends  of 
the    posts    and    the    top 
ends     of    the     diagonal 
braces  H,   which  stiffen 
the      whole       structure 
lengthways.    When  con 
structing  this  shed    the  posts,    braces 
and  stringers  should    first    be  framed, 
put    together,    raised   and  temporarily 
braced    across  before    commencing    to 
frame  the  truss  roof. 

Before  commencing  the  latter  a  close 
study  should  be  made  of  the  different 
constructive  details  of  the  roof  and  the 
lengths  and  forms  carefully  noted  and 
studied  out  in  order  not  to  spoil  any  of 
the  timber. 

The  first  important  detail  is  the 
straining  beam  B  This  stick  should  be 
procured  50'  0"  long,  laid  out  and 
wrought  as  follows:  First,  the  proper 
position  of  the  stringers  A.  24'0"between 
centres  is  laid  out  on  the  underside,  also 
laid  out  and  gained  for  the  braces  D. 
Then  directly  in  the  centre  of  this  dis- 
tance on  the  top  side  of  the  beam,  the 
position  of  the  king  tie  C,  is  laid  off  and 
distinctly  marked.  Directly  over  the 
position  of  the  stringers  a  mortise  to  re- 
ceive the  short  6"  x  10"  posts  F  is  made 
on  both  ends,  also  the  opposite  ends  are 
notched  or  gained  out  for  the  feet  of 
the  principal  rafters  E.  in  the  manner 
shown,  about  2"  down  in  the  beam. 


50 


ROOF  FRAMING  MADE  EASY 


ROOF  FRAMING  MADE  EASY. 


51 


I 

en 
W 


52 


ROOF  FRAMING  MADE  EASY. 


Next  the  principal  rafters  G,  are  mor- 
tised out  for  the  short  posts,  cut  to  the 
exact  length  as  given,  to  the  top  bevel 
and  notch  required  to  fit  into  the  strain- 
ing beatn.  It  is  also  bored  out  for  the 
wrought  iron  rods  and  bolts  G.  delin- 
eated. The  straining  beams  are  like- 
wise bored  for  these  irons.  The  short 
posts  F,  and  braces  D  are  finally  framed 
with  the  usual  tenons  and  the  trusts  is 
ready  to  be  put  together . 

In  doing  this  the  proper  way  to  pro- 
ceed is  to  first  set  the  straining  beam  B. 
then  to  insert  the  tenons  of  the  short 
posts  F,  into  their  mortises,  next  the 
king  tie  C,  and  finally  the  principal 
rafters  E.  The  vertical  bolts  I,  and 
washers  are  next  inserted andthe  straps 
J  put  on.  This  operation  must  of  course 
be  gone  through  on  each  truss,  and  the 
whole  number  finished  before  commenc- 
ing to  raise  them  into  their  permanent 
position  on  top  of  the  stringer  beams 
A  A.  The  raising  can  be  done  with  a 
good  gi^n  pole  or  derrick.  When  the 
trusses  are  set  vertically  on  stringers 
AA,  to  form  the  appearance  seen  in  the 
engraving,  directly  over  the  posts  be- 
low, each  one  should  be  well  braced 
with  2"  x  4"  joists  to  prevent  it  from  be- 
ing blown  or  knocked  down.  Each 
truss  should  also  be  set  perfectly  plumb 
sideways.  If  desired,  the  outer  braces 
KK  may  be  omitted  and  the  wrought 
iron  rod  G  inserted  to  counterbalance 
the  overhanging  portion  of  the  roof. 
The  space  inside  the  braces  may  also  be 
filled  in  with  ornamental  scroll  work, 
either  in  iron  or  wood.  In  regard 
to  the  strains  on  the  different  timbers 
I  would  say  that  the  straining  beam 
B  is  in  tension,  the  braces  K  and  D 
underneath  to  the  posts  are  in  com- 
pression. The  principal  rafters  are  in 
compression.  The  king  tie  C  is  in 
compression  and  the  purlins  bear  a 
lateral  strain  across  the  fibres.  The 
bolts  are  wrought  iron.  The  washers 
and  plates  cast  iron  Straps  .are  of 
wrought  iron  |"  x  2".  This  roof  may 
be  safely  covered  with  shingles,  or 
metal  shingles,  or  tar  paper. 


It  will  be  noticed  that  I  have  given  in 
this  description  a  full  written  and  de- 
tailed description  of  the  construction  of 
this  roof  and  ''mode  of  procedure" 
necessary  to  be  followed  in  building  it. 
The  years  which  I  have  studied  con- 
struction have  taught  me  that  much 
detailed  information  is  never  superfluous 
in  conveying  accurate  mechanical  prac- 
tice to  others. 

The  truss  illustrated  at  Fig.  76  was 
designed  by  Walter  P.  Rice,  C.  E.. 
of  Cleveland,  Ohio,  for  the  roof  of  the 
grand  stand  at  the  baseball  park  in 
that  city,  and  reflects  great  credit  on 
him  for  the  economical  manner  in 
which  he  disposed  of  the  constructive 
details  in  such  a  way  as  to  leave  a  view 
of  the  field  unobstructed.  As  will  be 
seen  on  reference  to  the  plan  the  portion 
of  the  roof  where  the  cantilevers  were 
employed  covered  the  portion  on  the 
corners  which  was  contained  in  the  two 
sides  placed  at  right  angles,  and  had  a 
post  been  placed  under  each  truss  the 
view  of  the  field  would  have  been  much 
intercepted  To  avoid  this  he  suspended 
the  intervening  trusses  shown  by  the 
dotted  lines  on  the  plan  on  iron  rods 
which  were  carried  over  those  trusses 
resting  on  the  posts,  thus  leaving  the 
space  below  clear  for  the  spectators  to 
see  the  players.  These  trusses  are  but 
slightly  different  in  form  from  those  in 
ordinary  roofs,  though  the  static  con- 
ditions are  changed  on  account  of  the 
cantilever  form.  The  drawing  will  ex 
plain  to  readers  its  form  and  show  how 
judiciously  and  economically  the  pieces 
were  proportioned,  also  how  the  engi- 
neer, realizing  by  calculation  that  the 
greater  part  of  the  vertical  strain  would 
necessarily  be  exerted  on  the  front  col 
umns,  increased  its  efficiency  by  using 
an  iron  post  of  the  diagonal  lattice  pat- 
tern of  the  proportions  shown.  The 
idea  is  an  excellent  one  and  worthy  of 
the  high  reputation  of  its  designer.  It 
need  scarcely  be  added  that  the  entire 
workmanship  of  the  whole  construction 
of  the  stand,  mostly  timber,  was  done  in 
the  most  creditable  manner. 


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